Source/WebCore/accessibility/AccessibilityRenderObject.cpp - WebKit - Git at Google

 /*
 * Copyright (C) 2008 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

 #include "config.h"
 #include "AccessibilityRenderObject.h"

 #include "AXObjectCache.h"
 #include "AccessibilityImageMapLink.h"
 #include "AccessibilityListBox.h"
 #include "AccessibilitySVGRoot.h"
 #include "AccessibilitySpinButton.h"
 #include "AccessibilityTable.h"
 #include "CachedImage.h"
 #include "Chrome.h"
 #include "ElementIterator.h"
 #include "EventNames.h"
 #include "FloatRect.h"
 #include "Frame.h"
 #include "FrameLoader.h"
 #include "FrameSelection.h"
 #include "HTMLAreaElement.h"
 #include "HTMLFormElement.h"
 #include "HTMLFrameElementBase.h"
 #include "HTMLImageElement.h"
 #include "HTMLInputElement.h"
 #include "HTMLLabelElement.h"
 #include "HTMLMapElement.h"
 #include "HTMLNames.h"
 #include "HTMLOptGroupElement.h"
 #include "HTMLOptionElement.h"
 #include "HTMLOptionsCollection.h"
 #include "HTMLSelectElement.h"
 #include "HTMLTableElement.h"
 #include "HTMLTextAreaElement.h"
 #include "HitTestRequest.h"
 #include "HitTestResult.h"
 #include "Image.h"
 #include "LocalizedStrings.h"
 #include "MathMLNames.h"
 #include "NodeList.h"
 #include "Page.h"
 #include "ProgressTracker.h"
 #include "RenderBR.h"
 #include "RenderButton.h"
 #include "RenderFieldset.h"
 #include "RenderFileUploadControl.h"
 #include "RenderHTMLCanvas.h"
 #include "RenderImage.h"
 #include "RenderInline.h"
 #include "RenderLayer.h"
 #include "RenderListBox.h"
 #include "RenderListMarker.h"
 #include "RenderMathMLBlock.h"
 #include "RenderMathMLFraction.h"
 #include "RenderMathMLOperator.h"
 #include "RenderMenuList.h"
 #include "RenderSVGShape.h"
 #include "RenderText.h"
 #include "RenderTextControl.h"
 #include "RenderTextControlSingleLine.h"
 #include "RenderTextFragment.h"
 #include "RenderTheme.h"
 #include "RenderView.h"
 #include "RenderWidget.h"
 #include "RenderedPosition.h"
 #include "SVGDocument.h"
 #include "SVGImage.h"
 #include "SVGImageChromeClient.h"
 #include "SVGNames.h"
 #include "SVGSVGElement.h"
 #include "Text.h"
 #include "TextControlInnerElements.h"
 #include "VisibleUnits.h"
 #include "htmlediting.h"
 #include <wtf/StdLibExtras.h>
 #include <wtf/text/StringBuilder.h>
 #include <wtf/unicode/CharacterNames.h>

 using namespace std;

 namespace WebCore {

 using namespace HTMLNames;

 AccessibilityRenderObject::AccessibilityRenderObject(RenderObject* renderer)
     : AccessibilityNodeObject(renderer->node())
     , m_renderer(renderer)
 {
 #ifndef NDEBUG
     m_renderer->setHasAXObject(true);
 #endif
 }

 AccessibilityRenderObject::~AccessibilityRenderObject()
 {
     ASSERT(isDetached());
 }

 void AccessibilityRenderObject::init()
 {
     AccessibilityNodeObject::init();
 }

 PassRefPtr<AccessibilityRenderObject> AccessibilityRenderObject::create(RenderObject* renderer)
 {
     return adoptRef(new AccessibilityRenderObject(renderer));
 }

 void AccessibilityRenderObject::detach()
 {
     AccessibilityNodeObject::detach();

     detachRemoteSVGRoot();

 #ifndef NDEBUG
     if (m_renderer)
         m_renderer->setHasAXObject(false);
 #endif
     m_renderer = 0;
 }

 RenderBoxModelObject* AccessibilityRenderObject::renderBoxModelObject() const
 {
     if (!m_renderer || !m_renderer->isBoxModelObject())
         return 0;
     return toRenderBoxModelObject(m_renderer);
 }

 void AccessibilityRenderObject::setRenderer(RenderObject* renderer)
 {
     m_renderer = renderer;
     setNode(renderer->node());
 }

 static inline bool isInlineWithContinuation(RenderObject* object)
 {
     if (!object->isBoxModelObject())
         return false;

     RenderBoxModelObject* renderer = toRenderBoxModelObject(object);
     if (!renderer->isRenderInline())
         return false;

     return toRenderInline(renderer)->continuation();
 }

 static inline RenderObject* firstChildInContinuation(RenderObject* renderer)
 {
     RenderObject* r = toRenderInline(renderer)->continuation();

     while (r) {
         if (r->isRenderBlock())
             return r;
         if (RenderObject* child = r->firstChild())
             return child;
         r = toRenderInline(r)->continuation();
     }

     return 0;
 }

 static inline RenderObject* firstChildConsideringContinuation(RenderObject* renderer)
 {
     RenderObject* firstChild = renderer->firstChild();

     if (!firstChild && isInlineWithContinuation(renderer))
         firstChild = firstChildInContinuation(renderer);

     return firstChild;
 }


 static inline RenderObject* lastChildConsideringContinuation(RenderObject* renderer)
 {
     RenderObject* lastChild = renderer->lastChild();
     RenderObject* prev;
     RenderObject* cur = renderer;

     if (!cur->isRenderInline() && !cur->isRenderBlock())
         return renderer;

     while (cur) {
         prev = cur;

         if (RenderObject* lc = cur->lastChild())
             lastChild = lc;

         if (cur->isRenderInline()) {
             cur = toRenderInline(cur)->inlineElementContinuation();
             ASSERT_UNUSED(prev, cur || !toRenderInline(prev)->continuation());
         } else
             cur = toRenderBlock(cur)->inlineElementContinuation();
     }

     return lastChild;
 }

 AccessibilityObject* AccessibilityRenderObject::firstChild() const
 {
     if (!m_renderer)
         return 0;

     RenderObject* firstChild = firstChildConsideringContinuation(m_renderer);

     // If an object can't have children, then it is using this method to help
     // calculate some internal property (like its description).
     // In this case, it should check the Node level for children in case they're
     // not rendered (like a <meter> element).
     if (!firstChild && !canHaveChildren())
         return AccessibilityNodeObject::firstChild();

     return axObjectCache()->getOrCreate(firstChild);
 }

 AccessibilityObject* AccessibilityRenderObject::lastChild() const
 {
     if (!m_renderer)
         return 0;

     RenderObject* lastChild = lastChildConsideringContinuation(m_renderer);

     if (!lastChild && !canHaveChildren())
         return AccessibilityNodeObject::lastChild();

     return axObjectCache()->getOrCreate(lastChild);
 }

 static inline RenderInline* startOfContinuations(RenderObject* r)
 {
     if (r->isInlineElementContinuation()) {
 #if ENABLE(MATHML)
         // MathML elements make anonymous RenderObjects, then set their node to the parent's node.
         // This makes it so that the renderer() != renderer()->node()->renderer()
         // (which is what isInlineElementContinuation() uses as a determinant).
         if (r->node()->isElementNode() && toElement(r->node())->isMathMLElement())
             return 0;
 #endif

         return toRenderInline(r->node()->renderer());
     }

     // Blocks with a previous continuation always have a next continuation
     if (r->isRenderBlock() && toRenderBlock(r)->inlineElementContinuation())
         return toRenderInline(toRenderBlock(r)->inlineElementContinuation()->element()->renderer());

     return 0;
 }

 static inline RenderObject* endOfContinuations(RenderObject* renderer)
 {
     RenderObject* prev = renderer;
     RenderObject* cur = renderer;

     if (!cur->isRenderInline() && !cur->isRenderBlock())
         return renderer;

     while (cur) {
         prev = cur;
         if (cur->isRenderInline()) {
             cur = toRenderInline(cur)->inlineElementContinuation();
             ASSERT(cur || !toRenderInline(prev)->continuation());
         } else
             cur = toRenderBlock(cur)->inlineElementContinuation();
     }

     return prev;
 }


 static inline RenderObject* childBeforeConsideringContinuations(RenderInline* r, RenderObject* child)
 {
     RenderBoxModelObject* curContainer = r;
     RenderObject* cur = 0;
     RenderObject* prev = 0;

     while (curContainer) {
         if (curContainer->isRenderInline()) {
             cur = curContainer->firstChild();
             while (cur) {
                 if (cur == child)
                     return prev;
                 prev = cur;
                 cur = cur->nextSibling();
             }

             curContainer = toRenderInline(curContainer)->continuation();
         } else if (curContainer->isRenderBlock()) {
             if (curContainer == child)
                 return prev;

             prev = curContainer;
             curContainer = toRenderBlock(curContainer)->inlineElementContinuation();
         }
     }

     ASSERT_NOT_REACHED();

     return 0;
 }

 static inline bool firstChildIsInlineContinuation(RenderObject* renderer)
 {
     return renderer->firstChild() && renderer->firstChild()->isInlineElementContinuation();
 }

 AccessibilityObject* AccessibilityRenderObject::previousSibling() const
 {
     if (!m_renderer)
         return 0;

     RenderObject* previousSibling = 0;

     // Case 1: The node is a block and is an inline's continuation. In that case, the inline's
     // last child is our previous sibling (or further back in the continuation chain)
     RenderInline* startOfConts;
     if (m_renderer->isRenderBlock() && (startOfConts = startOfContinuations(m_renderer)))
         previousSibling = childBeforeConsideringContinuations(startOfConts, m_renderer);

     // Case 2: Anonymous block parent of the end of a continuation - skip all the way to before
     // the parent of the start, since everything in between will be linked up via the continuation.
     else if (m_renderer->isAnonymousBlock() && firstChildIsInlineContinuation(m_renderer)) {
         RenderObject* firstParent = startOfContinuations(m_renderer->firstChild())->parent();
         while (firstChildIsInlineContinuation(firstParent))
             firstParent = startOfContinuations(firstParent->firstChild())->parent();
         previousSibling = firstParent->previousSibling();
     }

     // Case 3: The node has an actual previous sibling
     else if (RenderObject* ps = m_renderer->previousSibling())
         previousSibling = ps;

     // Case 4: This node has no previous siblings, but its parent is an inline,
     // and is another node's inline continutation. Follow the continuation chain.
     else if (m_renderer->parent()->isRenderInline() && (startOfConts = startOfContinuations(m_renderer->parent())))
         previousSibling = childBeforeConsideringContinuations(startOfConts, m_renderer->parent()->firstChild());

     if (!previousSibling)
         return 0;

     return axObjectCache()->getOrCreate(previousSibling);
 }

 static inline bool lastChildHasContinuation(RenderObject* renderer)
 {
     return renderer->lastChild() && isInlineWithContinuation(renderer->lastChild());
 }

 AccessibilityObject* AccessibilityRenderObject::nextSibling() const
 {
     if (!m_renderer)
         return 0;

     RenderObject* nextSibling = 0;

     // Case 1: node is a block and has an inline continuation. Next sibling is the inline continuation's
     // first child.
     RenderInline* inlineContinuation;
     if (m_renderer->isRenderBlock() && (inlineContinuation = toRenderBlock(m_renderer)->inlineElementContinuation()))
         nextSibling = firstChildConsideringContinuation(inlineContinuation);

     // Case 2: Anonymous block parent of the start of a continuation - skip all the way to
     // after the parent of the end, since everything in between will be linked up via the continuation.
     else if (m_renderer->isAnonymousBlock() && lastChildHasContinuation(m_renderer)) {
         RenderObject* lastParent = endOfContinuations(m_renderer->lastChild())->parent();
         while (lastChildHasContinuation(lastParent))
             lastParent = endOfContinuations(lastParent->lastChild())->parent();
         nextSibling = lastParent->nextSibling();
     }

     // Case 3: node has an actual next sibling
     else if (RenderObject* ns = m_renderer->nextSibling())
         nextSibling = ns;

     // Case 4: node is an inline with a continuation. Next sibling is the next sibling of the end
     // of the continuation chain.
     else if (isInlineWithContinuation(m_renderer))
         nextSibling = endOfContinuations(m_renderer)->nextSibling();

     // Case 5: node has no next sibling, and its parent is an inline with a continuation.
     else if (isInlineWithContinuation(m_renderer->parent())) {
         RenderObject* continuation = toRenderInline(m_renderer->parent())->continuation();

         // Case 5a: continuation is a block - in this case the block itself is the next sibling.
         if (continuation->isRenderBlock())
             nextSibling = continuation;
         // Case 5b: continuation is an inline - in this case the inline's first child is the next sibling
         else
             nextSibling = firstChildConsideringContinuation(continuation);
     }

     if (!nextSibling)
         return 0;

     return axObjectCache()->getOrCreate(nextSibling);
 }

 static RenderBoxModelObject* nextContinuation(RenderObject* renderer)
 {
     ASSERT(renderer);
     if (renderer->isRenderInline() && !renderer->isReplaced())
         return toRenderInline(renderer)->continuation();
     if (renderer->isRenderBlock())
         return toRenderBlock(renderer)->inlineElementContinuation();
     return 0;
 }

 RenderObject* AccessibilityRenderObject::renderParentObject() const
 {
     if (!m_renderer)
         return 0;

     RenderObject* parent = m_renderer->parent();

     // Case 1: node is a block and is an inline's continuation. Parent
     // is the start of the continuation chain.
     RenderObject* startOfConts = 0;
     RenderObject* firstChild = 0;
     if (m_renderer->isRenderBlock() && (startOfConts = startOfContinuations(m_renderer)))
         parent = startOfConts;

     // Case 2: node's parent is an inline which is some node's continuation; parent is
     // the earliest node in the continuation chain.
     else if (parent && parent->isRenderInline() && (startOfConts = startOfContinuations(parent)))
         parent = startOfConts;

     // Case 3: The first sibling is the beginning of a continuation chain. Find the origin of that continuation.
     else if (parent && (firstChild = parent->firstChild()) && firstChild->node()) {
         // Get the node's renderer and follow that continuation chain until the first child is found
         RenderObject* nodeRenderFirstChild = firstChild->node()->renderer();
         while (nodeRenderFirstChild != firstChild) {
             for (RenderObject* contsTest = nodeRenderFirstChild; contsTest; contsTest = nextContinuation(contsTest)) {
                 if (contsTest == firstChild) {
                     parent = nodeRenderFirstChild->parent();
                     break;
                 }
             }
             if (firstChild == parent->firstChild())
                 break;
             firstChild = parent->firstChild();
             if (!firstChild->node())
                 break;
             nodeRenderFirstChild = firstChild->node()->renderer();
         }
     }

     return parent;
 }

 AccessibilityObject* AccessibilityRenderObject::parentObjectIfExists() const
 {
     // WebArea's parent should be the scroll view containing it.
     if (isWebArea() || isSeamlessWebArea())
         return axObjectCache()->get(&m_renderer->view().frameView());

     return axObjectCache()->get(renderParentObject());
 }

 AccessibilityObject* AccessibilityRenderObject::parentObject() const
 {
     if (!m_renderer)
         return 0;

     if (ariaRoleAttribute() == MenuBarRole)
         return axObjectCache()->getOrCreate(m_renderer->parent());

     // menuButton and its corresponding menu are DOM siblings, but Accessibility needs them to be parent/child
     if (ariaRoleAttribute() == MenuRole) {
         AccessibilityObject* parent = menuButtonForMenu();
         if (parent)
             return parent;
     }

     RenderObject* parentObj = renderParentObject();
     if (parentObj)
         return axObjectCache()->getOrCreate(parentObj);

     // WebArea's parent should be the scroll view containing it.
     if (isWebArea() || isSeamlessWebArea())
         return axObjectCache()->getOrCreate(&m_renderer->view().frameView());

     return 0;
 }

 bool AccessibilityRenderObject::isAttachment() const
 {
     RenderBoxModelObject* renderer = renderBoxModelObject();
     if (!renderer)
         return false;
     // Widgets are the replaced elements that we represent to AX as attachments
     bool isWidget = renderer->isWidget();

     return isWidget && ariaRoleAttribute() == UnknownRole;
 }

 bool AccessibilityRenderObject::isFileUploadButton() const
 {
     if (m_renderer && m_renderer->node() && isHTMLInputElement(m_renderer->node())) {
         HTMLInputElement* input = toHTMLInputElement(m_renderer->node());
         return input->isFileUpload();
     }

     return false;
 }

 bool AccessibilityRenderObject::isReadOnly() const
 {
     ASSERT(m_renderer);

     if (isWebArea()) {
         if (HTMLElement* body = m_renderer->document().body()) {
             if (body->rendererIsEditable())
                 return false;
         }

         return !m_renderer->document().rendererIsEditable();
     }

     return AccessibilityNodeObject::isReadOnly();
 }

 bool AccessibilityRenderObject::isOffScreen() const
 {
     ASSERT(m_renderer);
     IntRect contentRect = pixelSnappedIntRect(m_renderer->absoluteClippedOverflowRect());
     IntRect viewRect = m_renderer->view().frameView().visibleContentRect();
     viewRect.intersect(contentRect);
     return viewRect.isEmpty();
 }

 Element* AccessibilityRenderObject::anchorElement() const
 {
     if (!m_renderer)
         return 0;

     AXObjectCache* cache = axObjectCache();
     RenderObject* currRenderer;

     // Search up the render tree for a RenderObject with a DOM node.  Defer to an earlier continuation, though.
     for (currRenderer = m_renderer; currRenderer && !currRenderer->node(); currRenderer = currRenderer->parent()) {
         if (currRenderer->isAnonymousBlock()) {
             RenderObject* continuation = toRenderBlock(currRenderer)->continuation();
             if (continuation)
                 return cache->getOrCreate(continuation)->anchorElement();
         }
     }

     // bail if none found
     if (!currRenderer)
         return 0;

     // search up the DOM tree for an anchor element
     // NOTE: this assumes that any non-image with an anchor is an HTMLAnchorElement
     Node* node = currRenderer->node();
     for ( ; node; node = node->parentNode()) {
         if (isHTMLAnchorElement(node) || (node->renderer() && cache->getOrCreate(node->renderer())->isAnchor()))
             return toElement(node);
     }

     return 0;
 }

 String AccessibilityRenderObject::helpText() const
 {
     if (!m_renderer)
         return String();

     const AtomicString& ariaHelp = getAttribute(aria_helpAttr);
     if (!ariaHelp.isEmpty())
         return ariaHelp;

     String describedBy = ariaDescribedByAttribute();
     if (!describedBy.isEmpty())
         return describedBy;

     String description = accessibilityDescription();
     for (RenderObject* curr = m_renderer; curr; curr = curr->parent()) {
         if (curr->node() && curr->node()->isHTMLElement()) {
             const AtomicString& summary = toElement(curr->node())->getAttribute(summaryAttr);
             if (!summary.isEmpty())
                 return summary;

             // The title attribute should be used as help text unless it is already being used as descriptive text.
             const AtomicString& title = toElement(curr->node())->getAttribute(titleAttr);
             if (!title.isEmpty() && description != title)
                 return title;
         }

         // Only take help text from an ancestor element if its a group or an unknown role. If help was
         // added to those kinds of elements, it is likely it was meant for a child element.
         AccessibilityObject* axObj = axObjectCache()->getOrCreate(curr);
         if (axObj) {
             AccessibilityRole role = axObj->roleValue();
             if (role != GroupRole && role != UnknownRole)
                 break;
         }
     }

     return String();
 }

 String AccessibilityRenderObject::textUnderElement(AccessibilityTextUnderElementMode mode) const
 {
     if (!m_renderer)
         return String();

     if (m_renderer->isFileUploadControl())
         return toRenderFileUploadControl(m_renderer)->buttonValue();

     // Reflect when a content author has explicitly marked a line break.
     if (m_renderer->isBR())
         return ASCIILiteral("\n");

 #if ENABLE(MATHML)
     // Math operators create RenderText nodes on the fly that are not tied into the DOM in a reasonable way,
     // so rangeOfContents does not work for them (nor does regular text selection).
     if (m_renderer->isText() && isMathElement()) {
         for (RenderObject* parent = m_renderer->parent(); parent; parent = parent->parent()) {
             if (parent->isRenderMathMLBlock() && toRenderMathMLBlock(parent)->isRenderMathMLOperator())
                 return toRenderText(m_renderer)->text();
         }
     }
 #endif

     // We use a text iterator for text objects AND for those cases where we are
     // explicitly asking for the full text under a given element.
     if (m_renderer->isText() || mode.childrenInclusion == AccessibilityTextUnderElementMode::TextUnderElementModeIncludeAllChildren) {
         // If possible, use a text iterator to get the text, so that whitespace
         // is handled consistently.
         if (Node* node = this->node()) {
             if (Frame* frame = node->document().frame()) {
                 // catch stale WebCoreAXObject (see <rdar://problem/3960196>)
                 if (frame->document() != &node->document())
                     return String();

                 return plainText(rangeOfContents(node).get(), textIteratorBehaviorForTextRange());
             }
         }

         // Sometimes text fragments don't have Nodes associated with them (like when
         // CSS content is used to insert text or when a RenderCounter is used.)
         if (m_renderer->isText()) {
             RenderText* renderTextObject = toRenderText(m_renderer);
             if (renderTextObject->isTextFragment())
                 return String(static_cast<RenderTextFragment*>(m_renderer)->contentString());

             return String(renderTextObject->text());
         }
     }

     return AccessibilityNodeObject::textUnderElement(mode);
 }

 Node* AccessibilityRenderObject::node() const
 {
     if (!m_renderer)
         return 0;
     if (m_renderer->isRenderView())
         return &m_renderer->document();
     return m_renderer->node();
 }

 String AccessibilityRenderObject::stringValue() const
 {
     if (!m_renderer)
         return String();

     if (isPasswordField())
         return passwordFieldValue();

     RenderBoxModelObject* cssBox = renderBoxModelObject();

     if (ariaRoleAttribute() == StaticTextRole) {
         String staticText = text();
         if (!staticText.length())
             staticText = textUnderElement();
         return staticText;
     }

     if (m_renderer->isText())
         return textUnderElement();

     if (cssBox && cssBox->isMenuList()) {
         // RenderMenuList will go straight to the text() of its selected item.
         // This has to be overridden in the case where the selected item has an ARIA label.
         HTMLSelectElement* selectElement = toHTMLSelectElement(m_renderer->node());
         int selectedIndex = selectElement->selectedIndex();
         const Vector<HTMLElement*> listItems = selectElement->listItems();
         if (selectedIndex >= 0 && static_cast<size_t>(selectedIndex) < listItems.size()) {
             const AtomicString& overriddenDescription = listItems[selectedIndex]->fastGetAttribute(aria_labelAttr);
             if (!overriddenDescription.isNull())
                 return overriddenDescription;
         }
         return toRenderMenuList(m_renderer)->text();
     }

     if (m_renderer->isListMarker())
         return toRenderListMarker(*m_renderer).text();

     if (isWebArea())
         return String();

     if (isTextControl())
         return text();

     if (m_renderer->isFileUploadControl())
         return toRenderFileUploadControl(m_renderer)->fileTextValue();

     // FIXME: We might need to implement a value here for more types
     // FIXME: It would be better not to advertise a value at all for the types for which we don't implement one;
     // this would require subclassing or making accessibilityAttributeNames do something other than return a
     // single static array.
     return String();
 }

 HTMLLabelElement* AccessibilityRenderObject::labelElementContainer() const
 {
     if (!m_renderer)
         return 0;

     // the control element should not be considered part of the label
     if (isControl())
         return 0;

     // find if this has a parent that is a label
     for (Node* parentNode = m_renderer->node(); parentNode; parentNode = parentNode->parentNode()) {
         if (isHTMLLabelElement(parentNode))
             return toHTMLLabelElement(parentNode);
     }

     return 0;
 }

 // The boundingBox for elements within the remote SVG element needs to be offset by its position
 // within the parent page, otherwise they are in relative coordinates only.
 void AccessibilityRenderObject::offsetBoundingBoxForRemoteSVGElement(LayoutRect& rect) const
 {
     for (AccessibilityObject* parent = parentObject(); parent; parent = parent->parentObject()) {
         if (parent->isAccessibilitySVGRoot()) {
             rect.moveBy(parent->parentObject()->boundingBoxRect().location());
             break;
         }
     }
 }

 LayoutRect AccessibilityRenderObject::boundingBoxRect() const
 {
     RenderObject* obj = m_renderer;

     if (!obj)
         return LayoutRect();

     if (obj->node()) // If we are a continuation, we want to make sure to use the primary renderer.
         obj = obj->node()->renderer();

     // absoluteFocusRingQuads will query the hierarchy below this element, which for large webpages can be very slow.
     // For a web area, which will have the most elements of any element, absoluteQuads should be used.
     // We should also use absoluteQuads for SVG elements, otherwise transforms won't be applied.
     Vector<FloatQuad> quads;
     bool isSVGRoot = false;
 #if ENABLE(SVG)
     if (obj->isSVGRoot())
         isSVGRoot = true;
 #endif
     if (obj->isText())
         toRenderText(obj)->absoluteQuads(quads, 0, RenderText::ClipToEllipsis);
     else if (isWebArea() || isSeamlessWebArea() || isSVGRoot)
         obj->absoluteQuads(quads);
     else
         obj->absoluteFocusRingQuads(quads);

     LayoutRect result = boundingBoxForQuads(obj, quads);

 #if ENABLE(SVG)
     Document* document = this->document();
     if (document && document->isSVGDocument())
         offsetBoundingBoxForRemoteSVGElement(result);
 #endif

     // The size of the web area should be the content size, not the clipped size.
     if (isWebArea() || isSeamlessWebArea())
         result.setSize(obj->view().frameView().contentsSize());

     return result;
 }

 LayoutRect AccessibilityRenderObject::checkboxOrRadioRect() const
 {
     if (!m_renderer)
         return LayoutRect();

     HTMLLabelElement* label = labelForElement(toElement(m_renderer->node()));
     if (!label || !label->renderer())
         return boundingBoxRect();

     LayoutRect labelRect = axObjectCache()->getOrCreate(label)->elementRect();
     labelRect.unite(boundingBoxRect());
     return labelRect;
 }

 LayoutRect AccessibilityRenderObject::elementRect() const
 {
     // a checkbox or radio button should encompass its label
     if (isCheckboxOrRadio())
         return checkboxOrRadioRect();

     return boundingBoxRect();
 }

 bool AccessibilityRenderObject::supportsPath() const
 {
 #if ENABLE(SVG)
     if (m_renderer && m_renderer->isSVGShape())
         return true;
 #endif

     return false;
 }

 Path AccessibilityRenderObject::elementPath() const
 {
 #if ENABLE(SVG)
     if (m_renderer && m_renderer->isSVGShape() && toRenderSVGShape(m_renderer)->hasPath()) {
         Path path = toRenderSVGShape(m_renderer)->path();

         // The SVG path is in terms of the parent's bounding box. The path needs to be offset to frame coordinates.
         for (RenderObject* parent = m_renderer->parent(); parent; parent = parent->parent()) {
             if (parent->isSVGRoot()) {
                 LayoutPoint parentOffset = axObjectCache()->getOrCreate(parent)->elementRect().location();
                 path.transform(AffineTransform().translate(parentOffset.x(), parentOffset.y()));
                 break;
             }
         }

         return path;
     }
 #endif

     return Path();
 }

 IntPoint AccessibilityRenderObject::clickPoint()
 {
     // Headings are usually much wider than their textual content. If the mid point is used, often it can be wrong.
     if (isHeading() && children().size() == 1)
         return children()[0]->clickPoint();

     // use the default position unless this is an editable web area, in which case we use the selection bounds.
     if (!isWebArea() || isReadOnly())
         return AccessibilityObject::clickPoint();

     VisibleSelection visSelection = selection();
     VisiblePositionRange range = VisiblePositionRange(visSelection.visibleStart(), visSelection.visibleEnd());
     IntRect bounds = boundsForVisiblePositionRange(range);
 #if PLATFORM(MAC)
     bounds.setLocation(m_renderer->view().frameView().screenToContents(bounds.location()));
 #endif
     return IntPoint(bounds.x() + (bounds.width() / 2), bounds.y() - (bounds.height() / 2));
 }

 AccessibilityObject* AccessibilityRenderObject::internalLinkElement() const
 {
     Element* element = anchorElement();
     if (!element)
         return 0;

     // Right now, we do not support ARIA links as internal link elements
     if (!isHTMLAnchorElement(element))
         return 0;
     HTMLAnchorElement* anchor = toHTMLAnchorElement(element);

     KURL linkURL = anchor->href();
     String fragmentIdentifier = linkURL.fragmentIdentifier();
     if (fragmentIdentifier.isEmpty())
         return 0;

     // check if URL is the same as current URL
     KURL documentURL = m_renderer->document().url();
     if (!equalIgnoringFragmentIdentifier(documentURL, linkURL))
         return 0;

     Node* linkedNode = m_renderer->document().findAnchor(fragmentIdentifier);
     if (!linkedNode)
         return 0;

     // The element we find may not be accessible, so find the first accessible object.
     return firstAccessibleObjectFromNode(linkedNode);
 }

 ESpeak AccessibilityRenderObject::speakProperty() const
 {
     if (!m_renderer)
         return AccessibilityObject::speakProperty();

     return m_renderer->style()->speak();
 }

 void AccessibilityRenderObject::addRadioButtonGroupMembers(AccessibilityChildrenVector& linkedUIElements) const
 {
     if (!m_renderer || roleValue() != RadioButtonRole)
         return;

     Node* node = m_renderer->node();
     if (!node || !isHTMLInputElement(node))
         return;

     HTMLInputElement* input = toHTMLInputElement(node);
     // if there's a form, then this is easy
     if (input->form()) {
         Vector<RefPtr<Node> > formElements;
         input->form()->getNamedElements(input->name(), formElements);

         unsigned len = formElements.size();
         for (unsigned i = 0; i < len; ++i) {
             Node* associateElement = formElements[i].get();
             if (AccessibilityObject* object = axObjectCache()->getOrCreate(associateElement))
                 linkedUIElements.append(object);
         }
     } else {
         RefPtr<NodeList> list = node->document().getElementsByTagName("input");
         unsigned len = list->length();
         for (unsigned i = 0; i < len; ++i) {
             if (isHTMLInputElement(list->item(i))) {
                 HTMLInputElement* associateElement = toHTMLInputElement(list->item(i));
                 if (associateElement->isRadioButton() && associateElement->name() == input->name()) {
                     if (AccessibilityObject* object = axObjectCache()->getOrCreate(associateElement))
                         linkedUIElements.append(object);
                 }
             }
         }
     }
 }

 // linked ui elements could be all the related radio buttons in a group
 // or an internal anchor connection
 void AccessibilityRenderObject::linkedUIElements(AccessibilityChildrenVector& linkedUIElements) const
 {
     ariaFlowToElements(linkedUIElements);

     if (isAnchor()) {
         AccessibilityObject* linkedAXElement = internalLinkElement();
         if (linkedAXElement)
             linkedUIElements.append(linkedAXElement);
     }

     if (roleValue() == RadioButtonRole)
         addRadioButtonGroupMembers(linkedUIElements);
 }

 bool AccessibilityRenderObject::hasTextAlternative() const
 {
     // ARIA: section 2A, bullet #3 says if aria-labeledby or aria-label appears, it should
     // override the "label" element association.
     return ariaAccessibilityDescription().length();
 }

 bool AccessibilityRenderObject::ariaHasPopup() const
 {
     return elementAttributeValue(aria_haspopupAttr);
 }

 bool AccessibilityRenderObject::supportsARIAFlowTo() const
 {
     return !getAttribute(aria_flowtoAttr).isEmpty();
 }

 void AccessibilityRenderObject::ariaFlowToElements(AccessibilityChildrenVector& flowTo) const
 {
     Vector<Element*> elements;
     elementsFromAttribute(elements, aria_flowtoAttr);

     AXObjectCache* cache = axObjectCache();
     unsigned count = elements.size();
     for (unsigned k = 0; k < count; ++k) {
         Element* element = elements[k];
         AccessibilityObject* flowToElement = cache->getOrCreate(element);
         if (flowToElement)
             flowTo.append(flowToElement);
     }

 }

 bool AccessibilityRenderObject::supportsARIADropping() const
 {
     const AtomicString& dropEffect = getAttribute(aria_dropeffectAttr);
     return !dropEffect.isEmpty();
 }

 bool AccessibilityRenderObject::supportsARIADragging() const
 {
     const AtomicString& grabbed = getAttribute(aria_grabbedAttr);
     return equalIgnoringCase(grabbed, "true") || equalIgnoringCase(grabbed, "false");
 }

 bool AccessibilityRenderObject::isARIAGrabbed()
 {
     return elementAttributeValue(aria_grabbedAttr);
 }

 void AccessibilityRenderObject::determineARIADropEffects(Vector<String>& effects)
 {
     const AtomicString& dropEffects = getAttribute(aria_dropeffectAttr);
     if (dropEffects.isEmpty()) {
         effects.clear();
         return;
     }

     String dropEffectsString = dropEffects.string();
     dropEffectsString.replace('\n', ' ');
     dropEffectsString.split(' ', effects);
 }

 bool AccessibilityRenderObject::exposesTitleUIElement() const
 {
     if (!isControl())
         return false;

     // If this control is ignored (because it's invisible),
     // then the label needs to be exposed so it can be visible to accessibility.
     if (accessibilityIsIgnored())
         return true;

     // When controls have their own descriptions, the title element should be ignored.
     if (hasTextAlternative())
         return false;

     return true;
 }

 AccessibilityObject* AccessibilityRenderObject::titleUIElement() const
 {
     if (!m_renderer)
         return 0;

     // if isFieldset is true, the renderer is guaranteed to be a RenderFieldset
     if (isFieldset())
         return axObjectCache()->getOrCreate(toRenderFieldset(m_renderer)->findLegend(RenderFieldset::IncludeFloatingOrOutOfFlow));

     Node* node = m_renderer->node();
     if (!node || !node->isElementNode())
         return 0;
     HTMLLabelElement* label = labelForElement(toElement(node));
     if (label && label->renderer())
         return axObjectCache()->getOrCreate(label);

     return 0;
 }

 bool AccessibilityRenderObject::isAllowedChildOfTree() const
 {
     // Determine if this is in a tree. If so, we apply special behavior to make it work like an AXOutline.
     AccessibilityObject* axObj = parentObject();
     bool isInTree = false;
     while (axObj) {
         if (axObj->isTree()) {
             isInTree = true;
             break;
         }
         axObj = axObj->parentObject();
     }

     // If the object is in a tree, only tree items should be exposed (and the children of tree items).
     if (isInTree) {
         AccessibilityRole role = roleValue();
         if (role != TreeItemRole && role != StaticTextRole)
             return false;
     }
     return true;
 }

 AccessibilityObjectInclusion AccessibilityRenderObject::defaultObjectInclusion() const
 {
     // The following cases can apply to any element that's a subclass of AccessibilityRenderObject.

     if (!m_renderer)
         return IgnoreObject;

     if (m_renderer->style()->visibility() != VISIBLE) {
         // aria-hidden is meant to override visibility as the determinant in AX hierarchy inclusion.
         if (equalIgnoringCase(getAttribute(aria_hiddenAttr), "false"))
             return DefaultBehavior;

         return IgnoreObject;
     }

     return AccessibilityObject::defaultObjectInclusion();
 }

 bool AccessibilityRenderObject::computeAccessibilityIsIgnored() const
 {
 #ifndef NDEBUG
     ASSERT(m_initialized);
 #endif

     // Check first if any of the common reasons cause this element to be ignored.
     // Then process other use cases that need to be applied to all the various roles
     // that AccessibilityRenderObjects take on.
     AccessibilityObjectInclusion decision = defaultObjectInclusion();
     if (decision == IncludeObject)
         return false;
     if (decision == IgnoreObject)
         return true;

     // If this element is within a parent that cannot have children, it should not be exposed.
     if (isDescendantOfBarrenParent())
         return true;

     if (roleValue() == IgnoredRole)
         return true;

     if (roleValue() == PresentationalRole || inheritsPresentationalRole())
         return true;

     // An ARIA tree can only have tree items and static text as children.
     if (!isAllowedChildOfTree())
         return true;

     // Allow the platform to decide if the attachment is ignored or not.
     if (isAttachment())
         return accessibilityIgnoreAttachment();

     // ignore popup menu items because AppKit does
     for (RenderObject* parent = m_renderer->parent(); parent; parent = parent->parent()) {
         if (parent->isBoxModelObject() && toRenderBoxModelObject(parent)->isMenuList())
             return true;
     }

     // find out if this element is inside of a label element.
     // if so, it may be ignored because it's the label for a checkbox or radio button
     AccessibilityObject* controlObject = correspondingControlForLabelElement();
     if (controlObject && !controlObject->exposesTitleUIElement() && controlObject->isCheckboxOrRadio())
         return true;

     if (m_renderer->isBR())
         return true;

     if (m_renderer->isText()) {
         // static text beneath MenuItems and MenuButtons are just reported along with the menu item, so it's ignored on an individual level
         AccessibilityObject* parent = parentObjectUnignored();
         if (parent && (parent->isMenuItem() || parent->ariaRoleAttribute() == MenuButtonRole))
             return true;
         RenderText* renderText = toRenderText(m_renderer);
         if (!renderText->firstTextBox())
             return true;

         // static text beneath TextControls is reported along with the text control text so it's ignored.
         for (AccessibilityObject* parent = parentObject(); parent; parent = parent->parentObject()) {
             if (parent->roleValue() == TextFieldRole)
                 return true;
         }

         // text elements that are just empty whitespace should not be returned
         return renderText->text()->containsOnlyWhitespace();
     }

     if (isHeading())
         return false;

     if (isLink())
         return false;

     // all controls are accessible
     if (isControl())
         return false;

     if (ariaRoleAttribute() != UnknownRole)
         return false;

     // don't ignore labels, because they serve as TitleUIElements
     Node* node = m_renderer->node();
     if (node && isHTMLLabelElement(node))
         return false;

     // Anything that is content editable should not be ignored.
     // However, one cannot just call node->rendererIsEditable() since that will ask if its parents
     // are also editable. Only the top level content editable region should be exposed.
     if (hasContentEditableAttributeSet())
         return false;

     // List items play an important role in defining the structure of lists. They should not be ignored.
     if (roleValue() == ListItemRole)
         return false;

     // if this element has aria attributes on it, it should not be ignored.
     if (supportsARIAAttributes())
         return false;

 #if ENABLE(MATHML)
     // First check if this is a special case within the math tree that needs to be ignored.
     if (isIgnoredElementWithinMathTree())
         return true;
     // Otherwise all other math elements are in the tree.
     if (isMathElement())
         return false;
 #endif

     // <span> tags are inline tags and not meant to convey information if they have no other aria
     // information on them. If we don't ignore them, they may emit signals expected to come from
     // their parent. In addition, because included spans are GroupRole objects, and GroupRole
     // objects are often containers with meaningful information, the inclusion of a span can have
     // the side effect of causing the immediate parent accessible to be ignored. This is especially
     // problematic for platforms which have distinct roles for textual block elements.
     if (node && node->hasTagName(spanTag))
         return true;

     if (m_renderer->isRenderBlockFlow() && m_renderer->childrenInline() && !canSetFocusAttribute())
         return !toRenderBlock(m_renderer)->firstLineBox() && !mouseButtonListener();

     // ignore images seemingly used as spacers
     if (isImage()) {

         // If the image can take focus, it should not be ignored, lest the user not be able to interact with something important.
         if (canSetFocusAttribute())
             return false;

         if (node && node->isElementNode()) {
             Element* elt = toElement(node);
             const AtomicString& alt = elt->getAttribute(altAttr);
             // don't ignore an image that has an alt tag
             if (!alt.string().containsOnlyWhitespace())
                 return false;
             // informal standard is to ignore images with zero-length alt strings
             if (!alt.isNull())
                 return true;
             // If an image has a title attribute on it, accessibility should be lenient and allow it to appear in the hierarchy (according to WAI-ARIA).
             if (!getAttribute(titleAttr).isEmpty())
                 return false;
         }

         if (isNativeImage()) {
             // check for one-dimensional image
             RenderImage* image = toRenderImage(m_renderer);
             if (image->height() <= 1 || image->width() <= 1)
                 return true;

             // check whether rendered image was stretched from one-dimensional file image
             if (image->cachedImage()) {
                 LayoutSize imageSize = image->cachedImage()->imageSizeForRenderer(m_renderer, image->view().zoomFactor());
                 return imageSize.height() <= 1 || imageSize.width() <= 1;
             }
         }
         return false;
     }

     if (isCanvas()) {
         if (canvasHasFallbackContent())
             return false;

         if (m_renderer->isBox()) {
             RenderBox* canvasBox = toRenderBox(m_renderer);
             if (canvasBox->height() <= 1 || canvasBox->width() <= 1)
                 return true;
         }
         // Otherwise fall through; use presence of help text, title, or description to decide.
     }

     if (isWebArea() || isSeamlessWebArea() || m_renderer->isListMarker())
         return false;

     // Using the help text, title or accessibility description (so we
     // check if there's some kind of accessible name for the element)
     // to decide an element's visibility is not as definitive as
     // previous checks, so this should remain as one of the last.
     //
     // These checks are simplified in the interest of execution speed;
     // for example, any element having an alt attribute will make it
     // not ignored, rather than just images.
     if (!getAttribute(aria_helpAttr).isEmpty() || !getAttribute(aria_describedbyAttr).isEmpty() || !getAttribute(altAttr).isEmpty() || !getAttribute(titleAttr).isEmpty())
         return false;

     // Don't ignore generic focusable elements like <div tabindex=0>
     // unless they're completely empty, with no children.
     if (isGenericFocusableElement() && node->firstChild())
         return false;

     if (!ariaAccessibilityDescription().isEmpty())
         return false;

 #if ENABLE(MATHML)
     if (!getAttribute(MathMLNames::alttextAttr).isEmpty())
         return false;
 #endif

     // Other non-ignored host language elements
     if (node && node->hasTagName(dfnTag))
         return false;

     // By default, objects should be ignored so that the AX hierarchy is not
     // filled with unnecessary items.
     return true;
 }

 bool AccessibilityRenderObject::isLoaded() const
 {
     return !m_renderer->document().parser();
 }

 double AccessibilityRenderObject::estimatedLoadingProgress() const
 {
     if (!m_renderer)
         return 0;

     if (isLoaded())
         return 1.0;

     Page* page = m_renderer->document().page();
     if (!page)
         return 0;

     return page->progress().estimatedProgress();
 }

 int AccessibilityRenderObject::layoutCount() const
 {
     if (!m_renderer->isRenderView())
         return 0;
     return toRenderView(*m_renderer).frameView().layoutCount();
 }

 String AccessibilityRenderObject::text() const
 {
     if (isPasswordField())
         return passwordFieldValue();

     return AccessibilityNodeObject::text();
 }

 int AccessibilityRenderObject::textLength() const
 {
     ASSERT(isTextControl());

     if (isPasswordField())
 #if PLATFORM(GTK)
         return passwordFieldValue().length();
 #else
         return -1; // need to return something distinct from 0
 #endif

     return text().length();
 }

 PlainTextRange AccessibilityRenderObject::ariaSelectedTextRange() const
 {
     Node* node = m_renderer->node();
     if (!node)
         return PlainTextRange();

     VisibleSelection visibleSelection = selection();
     RefPtr<Range> currentSelectionRange = visibleSelection.toNormalizedRange();
     if (!currentSelectionRange || !currentSelectionRange->intersectsNode(node, IGNORE_EXCEPTION))
         return PlainTextRange();

     int start = indexForVisiblePosition(visibleSelection.start());
     int end = indexForVisiblePosition(visibleSelection.end());

     return PlainTextRange(start, end - start);
 }

 String AccessibilityRenderObject::selectedText() const
 {
     ASSERT(isTextControl());

     if (isPasswordField())
         return String(); // need to return something distinct from empty string

     if (isNativeTextControl()) {
         HTMLTextFormControlElement& textControl = toRenderTextControl(m_renderer)->textFormControlElement();
         return textControl.selectedText();
     }

     if (ariaRoleAttribute() == UnknownRole)
         return String();

     return doAXStringForRange(ariaSelectedTextRange());
 }

 const AtomicString& AccessibilityRenderObject::accessKey() const
 {
     Node* node = m_renderer->node();
     if (!node)
         return nullAtom;
     if (!node->isElementNode())
         return nullAtom;
     return toElement(node)->getAttribute(accesskeyAttr);
 }

 VisibleSelection AccessibilityRenderObject::selection() const
 {
     return m_renderer->frame().selection().selection();
 }

 PlainTextRange AccessibilityRenderObject::selectedTextRange() const
 {
     ASSERT(isTextControl());

     if (isPasswordField())
         return PlainTextRange();

     AccessibilityRole ariaRole = ariaRoleAttribute();
     if (isNativeTextControl() && ariaRole == UnknownRole) {
         HTMLTextFormControlElement& textControl = toRenderTextControl(m_renderer)->textFormControlElement();
         return PlainTextRange(textControl.selectionStart(), textControl.selectionEnd() - textControl.selectionStart());
     }

     if (ariaRole == UnknownRole)
         return PlainTextRange();

     return ariaSelectedTextRange();
 }

 void AccessibilityRenderObject::setSelectedTextRange(const PlainTextRange& range)
 {
     if (isNativeTextControl()) {
         HTMLTextFormControlElement& textControl = toRenderTextControl(m_renderer)->textFormControlElement();
         textControl.setSelectionRange(range.start, range.start + range.length);
         return;
     }

     Node* node = m_renderer->node();
     m_renderer->frame().selection().setSelection(VisibleSelection(Position(node, range.start, Position::PositionIsOffsetInAnchor),
         Position(node, range.start + range.length, Position::PositionIsOffsetInAnchor), DOWNSTREAM));
 }

 KURL AccessibilityRenderObject::url() const
 {
     if (isAnchor() && isHTMLAnchorElement(m_renderer->node())) {
         if (HTMLAnchorElement* anchor = toHTMLAnchorElement(anchorElement()))
             return anchor->href();
     }

     if (isWebArea())
         return m_renderer->document().url();

     if (isImage() && m_renderer->node() && isHTMLImageElement(m_renderer->node()))
         return toHTMLImageElement(m_renderer->node())->src();

     if (isInputImage())
         return toHTMLInputElement(m_renderer->node())->src();

     return KURL();
 }

 bool AccessibilityRenderObject::isUnvisited() const
 {
     // FIXME: Is it a privacy violation to expose unvisited information to accessibility APIs?
     return m_renderer->style()->isLink() && m_renderer->style()->insideLink() == InsideUnvisitedLink;
 }

 bool AccessibilityRenderObject::isVisited() const
 {
     // FIXME: Is it a privacy violation to expose visited information to accessibility APIs?
     return m_renderer->style()->isLink() && m_renderer->style()->insideLink() == InsideVisitedLink;
 }

 void AccessibilityRenderObject::setElementAttributeValue(const QualifiedName& attributeName, bool value)
 {
     if (!m_renderer)
         return;

     Node* node = m_renderer->node();
     if (!node || !node->isElementNode())
         return;

     Element* element = toElement(node);
     element->setAttribute(attributeName, (value) ? "true" : "false");
 }

 bool AccessibilityRenderObject::elementAttributeValue(const QualifiedName& attributeName) const
 {
     if (!m_renderer)
         return false;

     return equalIgnoringCase(getAttribute(attributeName), "true");
 }

 bool AccessibilityRenderObject::isSelected() const
 {
     if (!m_renderer)
         return false;

     Node* node = m_renderer->node();
     if (!node)
         return false;

     const AtomicString& ariaSelected = getAttribute(aria_selectedAttr);
     if (equalIgnoringCase(ariaSelected, "true"))
         return true;

     if (isTabItem() && isTabItemSelected())
         return true;

     return false;
 }

 bool AccessibilityRenderObject::isTabItemSelected() const
 {
     if (!isTabItem() || !m_renderer)
         return false;

     Node* node = m_renderer->node();
     if (!node || !node->isElementNode())
         return false;

     // The ARIA spec says a tab item can also be selected if it is aria-labeled by a tabpanel
     // that has keyboard focus inside of it, or if a tabpanel in its aria-controls list has KB
     // focus inside of it.
     AccessibilityObject* focusedElement = focusedUIElement();
     if (!focusedElement)
         return false;

     Vector<Element*> elements;
     elementsFromAttribute(elements, aria_controlsAttr);

     unsigned count = elements.size();
     for (unsigned k = 0; k < count; ++k) {
         Element* element = elements[k];
         AccessibilityObject* tabPanel = axObjectCache()->getOrCreate(element);

         // A tab item should only control tab panels.
         if (!tabPanel || tabPanel->roleValue() != TabPanelRole)
             continue;

         AccessibilityObject* checkFocusElement = focusedElement;
         // Check if the focused element is a descendant of the element controlled by the tab item.
         while (checkFocusElement) {
             if (tabPanel == checkFocusElement)
                 return true;
             checkFocusElement = checkFocusElement->parentObject();
         }
     }

     return false;
 }

 bool AccessibilityRenderObject::isFocused() const
 {
     if (!m_renderer)
         return false;

     Document& document = m_renderer->document();

     Element* focusedElement = document.focusedElement();
     if (!focusedElement)
         return false;

     // A web area is represented by the Document node in the DOM tree, which isn't focusable.
     // Check instead if the frame's selection controller is focused
     if (focusedElement == m_renderer->node()
         || (roleValue() == WebAreaRole && document.frame()->selection().isFocusedAndActive()))
         return true;

     return false;
 }

 void AccessibilityRenderObject::setFocused(bool on)
 {
     if (!canSetFocusAttribute())
         return;

     Document* document = this->document();
     Node* node = this->node();

     if (!on || !node || !node->isElementNode()) {
         document->setFocusedElement(0);
         return;
     }

     // If this node is already the currently focused node, then calling focus() won't do anything.
     // That is a problem when focus is removed from the webpage to chrome, and then returns.
     // In these cases, we need to do what keyboard and mouse focus do, which is reset focus first.
     if (document->focusedElement() == node)
         document->setFocusedElement(0);

     toElement(node)->focus();
 }

 void AccessibilityRenderObject::setSelectedRows(AccessibilityChildrenVector& selectedRows)
 {
     // Setting selected only makes sense in trees and tables (and tree-tables).
     AccessibilityRole role = roleValue();
     if (role != TreeRole && role != TreeGridRole && role != TableRole)
         return;

     bool isMulti = isMultiSelectable();
     unsigned count = selectedRows.size();
     if (count > 1 && !isMulti)
         count = 1;

     for (unsigned k = 0; k < count; ++k)
         selectedRows[k]->setSelected(true);
 }

 void AccessibilityRenderObject::setValue(const String& string)
 {
     if (!m_renderer || !m_renderer->node() || !m_renderer->node()->isElementNode())
         return;
     Element* element = toElement(m_renderer->node());

     if (!m_renderer->isBoxModelObject())
         return;
     RenderBoxModelObject* renderer = toRenderBoxModelObject(m_renderer);

     // FIXME: Do we want to do anything here for ARIA textboxes?
     if (renderer->isTextField()) {
         // FIXME: This is not safe!  Other elements could have a TextField renderer.
         toHTMLInputElement(element)->setValue(string);
     } else if (renderer->isTextArea()) {
         // FIXME: This is not safe!  Other elements could have a TextArea renderer.
         toHTMLTextAreaElement(element)->setValue(string);
     }
 }

 void AccessibilityRenderObject::ariaOwnsElements(AccessibilityChildrenVector& axObjects) const
 {
     Vector<Element*> elements;
     elementsFromAttribute(elements, aria_ownsAttr);

     unsigned count = elements.size();
     for (unsigned k = 0; k < count; ++k) {
         RenderObject* render = elements[k]->renderer();
         AccessibilityObject* obj = axObjectCache()->getOrCreate(render);
         if (obj)
             axObjects.append(obj);
     }
 }

 bool AccessibilityRenderObject::supportsARIAOwns() const
 {
     if (!m_renderer)
         return false;
     const AtomicString& ariaOwns = getAttribute(aria_ownsAttr);

     return !ariaOwns.isEmpty();
 }

 RenderView* AccessibilityRenderObject::topRenderer() const
 {
     Document* topDoc = topDocument();
     if (!topDoc)
         return 0;

     return topDoc->renderView();
 }

 Document* AccessibilityRenderObject::document() const
 {
     if (!m_renderer)
         return 0;
     return &m_renderer->document();
 }

 Document* AccessibilityRenderObject::topDocument() const
 {
     if (!document())
         return 0;
     return document()->topDocument();
 }

 FrameView* AccessibilityRenderObject::topDocumentFrameView() const
 {
     RenderView* renderView = topRenderer();
     if (!renderView)
         return 0;
     return &renderView->view().frameView();
 }

 Widget* AccessibilityRenderObject::widget() const
 {
     if (!m_renderer->isBoxModelObject() || !toRenderBoxModelObject(m_renderer)->isWidget())
         return 0;
     return toRenderWidget(m_renderer)->widget();
 }

 AccessibilityObject* AccessibilityRenderObject::accessibilityParentForImageMap(HTMLMapElement* map) const
 {
     // find an image that is using this map
     if (!map)
         return 0;

     HTMLImageElement* imageElement = map->imageElement();
     if (!imageElement)
         return 0;

     return axObjectCache()->getOrCreate(imageElement);
 }

 void AccessibilityRenderObject::getDocumentLinks(AccessibilityChildrenVector& result)
 {
     Document& document = m_renderer->document();
     RefPtr<HTMLCollection> links = document.links();
     for (unsigned i = 0; Node* curr = links->item(i); i++) {
         RenderObject* obj = curr->renderer();
         if (obj) {
             RefPtr<AccessibilityObject> axobj = document.axObjectCache()->getOrCreate(obj);
             ASSERT(axobj);
             if (!axobj->accessibilityIsIgnored() && axobj->isLink())
                 result.append(axobj);
         } else {
             Node* parent = curr->parentNode();
             if (parent && isHTMLAreaElement(curr) && isHTMLMapElement(parent)) {
                 AccessibilityImageMapLink* areaObject = static_cast<AccessibilityImageMapLink*>(axObjectCache()->getOrCreate(ImageMapLinkRole));
                 HTMLMapElement* map = toHTMLMapElement(parent);
                 areaObject->setHTMLAreaElement(toHTMLAreaElement(curr));
                 areaObject->setHTMLMapElement(map);
                 areaObject->setParent(accessibilityParentForImageMap(map));

                 result.append(areaObject);
             }
         }
     }
 }

 FrameView* AccessibilityRenderObject::documentFrameView() const
 {
     if (!m_renderer)
         return 0;

     // this is the RenderObject's Document's Frame's FrameView
     return &m_renderer->view().frameView();
 }

 Widget* AccessibilityRenderObject::widgetForAttachmentView() const
 {
     if (!isAttachment())
         return 0;
     return toRenderWidget(m_renderer)->widget();
 }

 FrameView* AccessibilityRenderObject::frameViewIfRenderView() const
 {
     if (!m_renderer->isRenderView())
         return 0;
     // this is the RenderObject's Document's renderer's FrameView
     return &m_renderer->view().frameView();
 }

 // This function is like a cross-platform version of - (WebCoreTextMarkerRange*)textMarkerRange. It returns
 // a Range that we can convert to a WebCoreTextMarkerRange in the Obj-C file
 VisiblePositionRange AccessibilityRenderObject::visiblePositionRange() const
 {
     if (!m_renderer)
         return VisiblePositionRange();

     // construct VisiblePositions for start and end
     Node* node = m_renderer->node();
     if (!node)
         return VisiblePositionRange();

     VisiblePosition startPos = firstPositionInOrBeforeNode(node);
     VisiblePosition endPos = lastPositionInOrAfterNode(node);

     // the VisiblePositions are equal for nodes like buttons, so adjust for that
     // FIXME: Really?  [button, 0] and [button, 1] are distinct (before and after the button)
     // I expect this code is only hit for things like empty divs?  In which case I don't think
     // the behavior is correct here -- eseidel
     if (startPos == endPos) {
         endPos = endPos.next();
         if (endPos.isNull())
             endPos = startPos;
     }

     return VisiblePositionRange(startPos, endPos);
 }

 VisiblePositionRange AccessibilityRenderObject::visiblePositionRangeForLine(unsigned lineCount) const
 {
     if (!lineCount || !m_renderer)
         return VisiblePositionRange();

     // iterate over the lines
     // FIXME: this is wrong when lineNumber is lineCount+1,  because nextLinePosition takes you to the
     // last offset of the last line
     VisiblePosition visiblePos = m_renderer->view().positionForPoint(IntPoint());
     VisiblePosition savedVisiblePos;
     while (--lineCount) {
         savedVisiblePos = visiblePos;
         visiblePos = nextLinePosition(visiblePos, 0);
         if (visiblePos.isNull() || visiblePos == savedVisiblePos)
             return VisiblePositionRange();
     }

     // make a caret selection for the marker position, then extend it to the line
     // NOTE: ignores results of sel.modify because it returns false when
     // starting at an empty line.  The resulting selection in that case
     // will be a caret at visiblePos.
     FrameSelection selection;
     selection.setSelection(VisibleSelection(visiblePos));
     selection.modify(FrameSelection::AlterationExtend, DirectionRight, LineBoundary);

     return VisiblePositionRange(selection.selection().visibleStart(), selection.selection().visibleEnd());
 }

 VisiblePosition AccessibilityRenderObject::visiblePositionForIndex(int index) const
 {
     if (!m_renderer)
         return VisiblePosition();

     if (isNativeTextControl())
         return toRenderTextControl(m_renderer)->textFormControlElement().visiblePositionForIndex(index);

     if (!allowsTextRanges() && !m_renderer->isText())
         return VisiblePosition();

     Node* node = m_renderer->node();
     if (!node)
         return VisiblePosition();

     return visiblePositionForIndexUsingCharacterIterator(node, index);
 }

 int AccessibilityRenderObject::indexForVisiblePosition(const VisiblePosition& pos) const
 {
     if (isNativeTextControl())
         return toRenderTextControl(m_renderer)->textFormControlElement().indexForVisiblePosition(pos);

     if (!isTextControl())
         return 0;

     Node* node = m_renderer->node();
     if (!node)
         return 0;

     Position indexPosition = pos.deepEquivalent();
     if (indexPosition.isNull() || highestEditableRoot(indexPosition, HasEditableAXRole) != node)
         return 0;

 #if PLATFORM(GTK)
     // We need to consider replaced elements for GTK, as they will be
     // presented with the 'object replacement character' (0xFFFC).
     bool forSelectionPreservation = true;
 #else
     bool forSelectionPreservation = false;
 #endif

     return WebCore::indexForVisiblePosition(node, pos, forSelectionPreservation);
 }

 Element* AccessibilityRenderObject::rootEditableElementForPosition(const Position& position) const
 {
     // Find the root editable or pseudo-editable (i.e. having an editable ARIA role) element.
     Element* result = 0;

     Element* rootEditableElement = position.rootEditableElement();

     for (Element* e = position.element(); e && e != rootEditableElement; e = e->parentElement()) {
         if (nodeIsTextControl(e))
             result = e;
         if (e->hasTagName(bodyTag))
             break;
     }

     if (result)
         return result;

     return rootEditableElement;
 }

 bool AccessibilityRenderObject::nodeIsTextControl(const Node* node) const
 {
     if (!node)
         return false;

     const AccessibilityObject* axObjectForNode = axObjectCache()->getOrCreate(const_cast<Node*>(node));
     if (!axObjectForNode)
         return false;

     return axObjectForNode->isTextControl();
 }

 IntRect AccessibilityRenderObject::boundsForVisiblePositionRange(const VisiblePositionRange& visiblePositionRange) const
 {
     if (visiblePositionRange.isNull())
         return IntRect();

     // Create a mutable VisiblePositionRange.
     VisiblePositionRange range(visiblePositionRange);
     LayoutRect rect1 = range.start.absoluteCaretBounds();
     LayoutRect rect2 = range.end.absoluteCaretBounds();

     // readjust for position at the edge of a line.  This is to exclude line rect that doesn't need to be accounted in the range bounds
     if (rect2.y() != rect1.y()) {
         VisiblePosition endOfFirstLine = endOfLine(range.start);
         if (range.start == endOfFirstLine) {
             range.start.setAffinity(DOWNSTREAM);
             rect1 = range.start.absoluteCaretBounds();
         }
         if (range.end == endOfFirstLine) {
             range.end.setAffinity(UPSTREAM);
             rect2 = range.end.absoluteCaretBounds();
         }
     }

     LayoutRect ourrect = rect1;
     ourrect.unite(rect2);

     // if the rectangle spans lines and contains multiple text chars, use the range's bounding box intead
     if (rect1.maxY() != rect2.maxY()) {
         RefPtr<Range> dataRange = makeRange(range.start, range.end);
         LayoutRect boundingBox = dataRange->boundingBox();
         String rangeString = plainText(dataRange.get());
         if (rangeString.length() > 1 && !boundingBox.isEmpty())
             ourrect = boundingBox;
     }

 #if PLATFORM(MAC) && !PLATFORM(IOS)
     return m_renderer->view().frameView().contentsToScreen(pixelSnappedIntRect(ourrect));
 #else
     return pixelSnappedIntRect(ourrect);
 #endif
 }

 void AccessibilityRenderObject::setSelectedVisiblePositionRange(const VisiblePositionRange& range) const
 {
     if (range.start.isNull() || range.end.isNull())
         return;

     // make selection and tell the document to use it. if it's zero length, then move to that position
     if (range.start == range.end)
         m_renderer->frame().selection().moveTo(range.start, UserTriggered);
     else {
         VisibleSelection newSelection = VisibleSelection(range.start, range.end);
         m_renderer->frame().selection().setSelection(newSelection);
     }
 }

 VisiblePosition AccessibilityRenderObject::visiblePositionForPoint(const IntPoint& point) const
 {
     if (!m_renderer)
         return VisiblePosition();

     // convert absolute point to view coordinates
     RenderView* renderView = topRenderer();
     if (!renderView)
         return VisiblePosition();

 #if PLATFORM(MAC)
     FrameView* frameView = &renderView->frameView();
 #endif

     Node* innerNode = 0;

     // locate the node containing the point
     LayoutPoint pointResult;
     while (1) {
         LayoutPoint ourpoint;
 #if PLATFORM(MAC)
         ourpoint = frameView->screenToContents(point);
 #else
         ourpoint = point;
 #endif
         HitTestRequest request(HitTestRequest::ReadOnly |
                                HitTestRequest::Active);
         HitTestResult result(ourpoint);
         renderView->hitTest(request, result);
         innerNode = result.innerNode();
         if (!innerNode)
             return VisiblePosition();

         RenderObject* renderer = innerNode->renderer();
         if (!renderer)
             return VisiblePosition();

         pointResult = result.localPoint();

         // done if hit something other than a widget
         if (!renderer->isWidget())
             break;

         // descend into widget (FRAME, IFRAME, OBJECT...)
         Widget* widget = toRenderWidget(renderer)->widget();
         if (!widget || !widget->isFrameView())
             break;
         Frame& frame = toFrameView(widget)->frame();
         renderView = frame.document()->renderView();
 #if PLATFORM(MAC)
         frameView = toFrameView(widget);
 #endif
     }

     return innerNode->renderer()->positionForPoint(pointResult);
 }

 // NOTE: Consider providing this utility method as AX API
 VisiblePosition AccessibilityRenderObject::visiblePositionForIndex(unsigned indexValue, bool lastIndexOK) const
 {
     if (!isTextControl())
         return VisiblePosition();

     // lastIndexOK specifies whether the position after the last character is acceptable
     if (indexValue >= text().length()) {
         if (!lastIndexOK || indexValue > text().length())
             return VisiblePosition();
     }
     VisiblePosition position = visiblePositionForIndex(indexValue);
     position.setAffinity(DOWNSTREAM);
     return position;
 }

 // NOTE: Consider providing this utility method as AX API
 int AccessibilityRenderObject::index(const VisiblePosition& position) const
 {
     if (position.isNull() || !isTextControl())
         return -1;

     if (renderObjectContainsPosition(m_renderer, position.deepEquivalent()))
         return indexForVisiblePosition(position);

     return -1;
 }

 void AccessibilityRenderObject::lineBreaks(Vector<int>& lineBreaks) const
 {
     if (!isTextControl())
         return;

     VisiblePosition visiblePos = visiblePositionForIndex(0);
     VisiblePosition savedVisiblePos = visiblePos;
     visiblePos = nextLinePosition(visiblePos, 0);
     while (!visiblePos.isNull() && visiblePos != savedVisiblePos) {
         lineBreaks.append(indexForVisiblePosition(visiblePos));
         savedVisiblePos = visiblePos;
         visiblePos = nextLinePosition(visiblePos, 0);
     }
 }

 // Given a line number, the range of characters of the text associated with this accessibility
 // object that contains the line number.
 PlainTextRange AccessibilityRenderObject::doAXRangeForLine(unsigned lineNumber) const
 {
     if (!isTextControl())
         return PlainTextRange();

     // iterate to the specified line
     VisiblePosition visiblePos = visiblePositionForIndex(0);
     VisiblePosition savedVisiblePos;
     for (unsigned lineCount = lineNumber; lineCount; lineCount -= 1) {
         savedVisiblePos = visiblePos;
         visiblePos = nextLinePosition(visiblePos, 0);
         if (visiblePos.isNull() || visiblePos == savedVisiblePos)
             return PlainTextRange();
     }

     // Get the end of the line based on the starting position.
     VisiblePosition endPosition = endOfLine(visiblePos);

     int index1 = indexForVisiblePosition(visiblePos);
     int index2 = indexForVisiblePosition(endPosition);

     // add one to the end index for a line break not caused by soft line wrap (to match AppKit)
     if (endPosition.affinity() == DOWNSTREAM && endPosition.next().isNotNull())
         index2 += 1;

     // return nil rather than an zero-length range (to match AppKit)
     if (index1 == index2)
         return PlainTextRange();

     return PlainTextRange(index1, index2 - index1);
 }

 // The composed character range in the text associated with this accessibility object that
 // is specified by the given index value. This parameterized attribute returns the complete
 // range of characters (including surrogate pairs of multi-byte glyphs) at the given index.
 PlainTextRange AccessibilityRenderObject::doAXRangeForIndex(unsigned index) const
 {
     if (!isTextControl())
         return PlainTextRange();

     String elementText = text();
     if (!elementText.length() || index > elementText.length() - 1)
         return PlainTextRange();

     return PlainTextRange(index, 1);
 }

 // A substring of the text associated with this accessibility object that is
 // specified by the given character range.
 String AccessibilityRenderObject::doAXStringForRange(const PlainTextRange& range) const
 {
     if (!range.length)
         return String();

     if (!isTextControl())
         return String();

     String elementText = isPasswordField() ? passwordFieldValue() : text();
     if (range.start + range.length > elementText.length())
         return String();

     return elementText.substring(range.start, range.length);
 }

 // The bounding rectangle of the text associated with this accessibility object that is
 // specified by the given range. This is the bounding rectangle a sighted user would see
 // on the display screen, in pixels.
 IntRect AccessibilityRenderObject::doAXBoundsForRange(const PlainTextRange& range) const
 {
     if (allowsTextRanges())
         return boundsForVisiblePositionRange(visiblePositionRangeForRange(range));
     return IntRect();
 }

 AccessibilityObject* AccessibilityRenderObject::accessibilityImageMapHitTest(HTMLAreaElement* area, const IntPoint& point) const
 {
     if (!area)
         return 0;

     AccessibilityObject* parent = 0;
     for (Element* mapParent = area->parentElement(); mapParent; mapParent = mapParent->parentElement()) {
         if (isHTMLMapElement(mapParent)) {
             parent = accessibilityParentForImageMap(toHTMLMapElement(mapParent));
             break;
         }
     }
     if (!parent)
         return 0;

     AccessibilityObject::AccessibilityChildrenVector children = parent->children();

     unsigned count = children.size();
     for (unsigned k = 0; k < count; ++k) {
         if (children[k]->elementRect().contains(point))
             return children[k].get();
     }

     return 0;
 }

 AccessibilityObject* AccessibilityRenderObject::remoteSVGElementHitTest(const IntPoint& point) const
 {
     AccessibilityObject* remote = remoteSVGRootElement();
     if (!remote)
         return 0;

     IntSize offset = point - roundedIntPoint(boundingBoxRect().location());
     return remote->accessibilityHitTest(IntPoint(offset));
 }

 AccessibilityObject* AccessibilityRenderObject::elementAccessibilityHitTest(const IntPoint& point) const
 {
     if (isSVGImage())
         return remoteSVGElementHitTest(point);

     return AccessibilityObject::elementAccessibilityHitTest(point);
 }

 AccessibilityObject* AccessibilityRenderObject::accessibilityHitTest(const IntPoint& point) const
 {
     if (!m_renderer || !m_renderer->hasLayer())
         return 0;

     RenderLayer* layer = toRenderBox(m_renderer)->layer();

     HitTestRequest request(HitTestRequest::ReadOnly | HitTestRequest::Active | HitTestRequest::AccessibilityHitTest);
     HitTestResult hitTestResult = HitTestResult(point);
     layer->hitTest(request, hitTestResult);
     if (!hitTestResult.innerNode())
         return 0;
     Node* node = hitTestResult.innerNode()->deprecatedShadowAncestorNode();

     if (isHTMLAreaElement(node))
         return accessibilityImageMapHitTest(toHTMLAreaElement(node), point);

     if (isHTMLOptionElement(node))
         node = toHTMLOptionElement(node)->ownerSelectElement();

     RenderObject* obj = node->renderer();
     if (!obj)
         return 0;

     AccessibilityObject* result = obj->document().axObjectCache()->getOrCreate(obj);
     result->updateChildrenIfNecessary();

     // Allow the element to perform any hit-testing it might need to do to reach non-render children.
     result = result->elementAccessibilityHitTest(point);

     if (result && result->accessibilityIsIgnored()) {
         // If this element is the label of a control, a hit test should return the control.
         AccessibilityObject* controlObject = result->correspondingControlForLabelElement();
         if (controlObject && !controlObject->exposesTitleUIElement())
             return controlObject;

         result = result->parentObjectUnignored();
     }

     return result;
 }

 bool AccessibilityRenderObject::shouldNotifyActiveDescendant() const
 {
     // We want to notify that the combo box has changed its active descendant,
     // but we do not want to change the focus, because focus should remain with the combo box.
     if (isComboBox())
         return true;

     return shouldFocusActiveDescendant();
 }

 bool AccessibilityRenderObject::shouldFocusActiveDescendant() const
 {
     switch (ariaRoleAttribute()) {
     case GroupRole:
     case ListBoxRole:
     case MenuRole:
     case MenuBarRole:
     case RadioGroupRole:
     case RowRole:
     case PopUpButtonRole:
     case ProgressIndicatorRole:
     case ToolbarRole:
     case OutlineRole:
     case TreeRole:
     case GridRole:
     /* FIXME: replace these with actual roles when they are added to AccessibilityRole
     composite
     alert
     alertdialog
     status
     timer
     */
         return true;
     default:
         return false;
     }
 }

 AccessibilityObject* AccessibilityRenderObject::activeDescendant() const
 {
     if (!m_renderer)
         return 0;

     if (m_renderer->node() && !m_renderer->node()->isElementNode())
         return 0;
     Element* element = toElement(m_renderer->node());

     const AtomicString& activeDescendantAttrStr = element->getAttribute(aria_activedescendantAttr);
     if (activeDescendantAttrStr.isNull() || activeDescendantAttrStr.isEmpty())
         return 0;

     Element* target = element->treeScope()->getElementById(activeDescendantAttrStr);
     if (!target)
         return 0;

     AccessibilityObject* obj = axObjectCache()->getOrCreate(target);
     if (obj && obj->isAccessibilityRenderObject())
     // an activedescendant is only useful if it has a renderer, because that's what's needed to post the notification
         return obj;
     return 0;
 }

 void AccessibilityRenderObject::handleAriaExpandedChanged()
 {
     // Find if a parent of this object should handle aria-expanded changes.
     AccessibilityObject* containerParent = this->parentObject();
     while (containerParent) {
         bool foundParent = false;

         switch (containerParent->roleValue()) {
         case TreeRole:
         case TreeGridRole:
         case GridRole:
         case TableRole:
         case BrowserRole:
             foundParent = true;
             break;
         default:
             break;
         }

         if (foundParent)
             break;

         containerParent = containerParent->parentObject();
     }

     // Post that the row count changed.
     if (containerParent)
         axObjectCache()->postNotification(containerParent, document(), AXObjectCache::AXRowCountChanged, true);

     // Post that the specific row either collapsed or expanded.
     if (roleValue() == RowRole || roleValue() == TreeItemRole)
         axObjectCache()->postNotification(this, document(), isExpanded() ? AXObjectCache::AXRowExpanded : AXObjectCache::AXRowCollapsed, true);
 }

 void AccessibilityRenderObject::handleActiveDescendantChanged()
 {
     Element* element = toElement(renderer()->node());
     if (!element)
         return;
     if (!renderer()->frame().selection().isFocusedAndActive() || renderer()->document().focusedElement() != element)
         return;
     AccessibilityRenderObject* activedescendant = static_cast<AccessibilityRenderObject*>(activeDescendant());

     if (activedescendant && shouldNotifyActiveDescendant())
         renderer()->document().axObjectCache()->postNotification(m_renderer, AXObjectCache::AXActiveDescendantChanged, true);
 }

 AccessibilityObject* AccessibilityRenderObject::correspondingControlForLabelElement() const
 {
     HTMLLabelElement* labelElement = labelElementContainer();
     if (!labelElement)
         return 0;

     HTMLElement* correspondingControl = labelElement->control();
     if (!correspondingControl)
         return 0;

     // Make sure the corresponding control isn't a descendant of this label that's in the middle of being destroyed.
     if (correspondingControl->renderer() && !correspondingControl->renderer()->parent())
         return 0;

     return axObjectCache()->getOrCreate(correspondingControl);
 }

 AccessibilityObject* AccessibilityRenderObject::correspondingLabelForControlElement() const
 {
     if (!m_renderer)
         return 0;

     // ARIA: section 2A, bullet #3 says if aria-labeledby or aria-label appears, it should
     // override the "label" element association.
     if (hasTextAlternative())
         return 0;

     Node* node = m_renderer->node();
     if (node && node->isHTMLElement()) {
         HTMLLabelElement* label = labelForElement(toElement(node));
         if (label)
             return axObjectCache()->getOrCreate(label);
     }

     return 0;
 }

 bool AccessibilityRenderObject::renderObjectIsObservable(RenderObject* renderer) const
 {
     // AX clients will listen for AXValueChange on a text control.
     if (renderer->isTextControl())
         return true;

     // AX clients will listen for AXSelectedChildrenChanged on listboxes.
     Node* node = renderer->node();
     if (nodeHasRole(node, "listbox") || (renderer->isBoxModelObject() && toRenderBoxModelObject(renderer)->isListBox()))
         return true;

     // Textboxes should send out notifications.
     if (nodeHasRole(node, "textbox"))
         return true;

     return false;
 }

 AccessibilityObject* AccessibilityRenderObject::observableObject() const
 {
     // Find the object going up the parent chain that is used in accessibility to monitor certain notifications.
     for (RenderObject* renderer = m_renderer; renderer && renderer->node(); renderer = renderer->parent()) {
         if (renderObjectIsObservable(renderer))
             return axObjectCache()->getOrCreate(renderer);
     }

     return 0;
 }

 bool AccessibilityRenderObject::isDescendantOfElementType(const QualifiedName& tagName) const
 {
     for (RenderObject* parent = m_renderer->parent(); parent; parent = parent->parent()) {
         if (parent->node() && parent->node()->hasTagName(tagName))
             return true;
     }
     return false;
 }

 AccessibilityRole AccessibilityRenderObject::determineAccessibilityRole()
 {
     if (!m_renderer)
         return UnknownRole;

     m_ariaRole = determineAriaRoleAttribute();

     Node* node = m_renderer->node();
     AccessibilityRole ariaRole = ariaRoleAttribute();
     if (ariaRole != UnknownRole)
         return ariaRole;

     RenderBoxModelObject* cssBox = renderBoxModelObject();

     if (node && node->isLink()) {
         if (cssBox && cssBox->isImage())
             return ImageMapRole;
         return WebCoreLinkRole;
     }
     if ((cssBox && cssBox->isListItem()) || (node && node->hasTagName(liTag)))
         return ListItemRole;
     if (m_renderer->isListMarker())
         return ListMarkerRole;
     if (node && node->hasTagName(buttonTag))
         return buttonRoleType();
     if (node && node->hasTagName(legendTag))
         return LegendRole;
     if (m_renderer->isText())
         return StaticTextRole;
     if (cssBox && cssBox->isImage()) {
         if (node && isHTMLInputElement(node))
             return ariaHasPopup() ? PopUpButtonRole : ButtonRole;
         if (isSVGImage())
             return SVGRootRole;
         return ImageRole;
     }

     if (node && node->hasTagName(canvasTag))
         return CanvasRole;

     if (cssBox && cssBox->isRenderView()) {
         // If the iframe is seamless, it should not be announced as a web area to AT clients.
         if (document() && document()->shouldDisplaySeamlesslyWithParent())
             return SeamlessWebAreaRole;
         return WebAreaRole;
     }

     if (cssBox && cssBox->isTextField())
         return TextFieldRole;

     if (cssBox && cssBox->isTextArea())
         return TextAreaRole;

     if (node && isHTMLInputElement(node)) {
         HTMLInputElement* input = toHTMLInputElement(node);
         if (input->isCheckbox())
             return CheckBoxRole;
         if (input->isRadioButton())
             return RadioButtonRole;
         if (input->isTextButton())
             return buttonRoleType();

 #if ENABLE(INPUT_TYPE_COLOR)
         const AtomicString& type = input->getAttribute(typeAttr);
         if (equalIgnoringCase(type, "color"))
             return ColorWellRole;
 #endif
     }

     if (isFileUploadButton())
         return ButtonRole;

     if (cssBox && cssBox->isMenuList())
         return PopUpButtonRole;

     if (headingLevel())
         return HeadingRole;

 #if ENABLE(SVG)
     if (m_renderer->isSVGImage())
         return ImageRole;
     if (m_renderer->isSVGRoot())
         return SVGRootRole;
     if (node && node->hasTagName(SVGNames::gTag))
         return GroupRole;
 #endif

 #if ENABLE(MATHML)
     if (node && node->hasTagName(MathMLNames::mathTag))
         return DocumentMathRole;
 #endif
     // It's not clear which role a platform should choose for a math element.
     // Declaring a math element role should give flexibility to platforms to choose.
     if (isMathElement())
         return MathElementRole;

     if (node && node->hasTagName(ddTag))
         return DescriptionListDetailRole;

     if (node && node->hasTagName(dtTag))
         return DescriptionListTermRole;

     if (node && node->hasTagName(dlTag))
         return DescriptionListRole;

     if (node && (node->hasTagName(rpTag) || node->hasTagName(rtTag)))
         return AnnotationRole;

 #if PLATFORM(GTK)
     // Gtk ATs expect all tables, data and layout, to be exposed as tables.
     if (node && (node->hasTagName(tdTag) || node->hasTagName(thTag)))
         return CellRole;

     if (node && node->hasTagName(trTag))
         return RowRole;

     if (node && isHTMLTableElement(node))
         return TableRole;
 #endif

     // Table sections should be ignored.
     if (m_renderer->isTableSection())
         return IgnoredRole;

     if (m_renderer->isHR())
         return HorizontalRuleRole;

     if (node && node->hasTagName(pTag))
         return ParagraphRole;

     if (node && isHTMLLabelElement(node))
         return LabelRole;

     if (node && node->hasTagName(dfnTag))
         return DefinitionRole;

     if (node && node->hasTagName(divTag))
         return DivRole;

     if (node && isHTMLFormElement(node))
         return FormRole;

     if (node && node->hasTagName(articleTag))
         return DocumentArticleRole;

     if (node && node->hasTagName(mainTag))
         return LandmarkMainRole;

     if (node && node->hasTagName(navTag))
         return LandmarkNavigationRole;

     if (node && node->hasTagName(asideTag))
         return LandmarkComplementaryRole;

     if (node && node->hasTagName(sectionTag))
         return DocumentRegionRole;

     if (node && node->hasTagName(addressTag))
         return LandmarkContentInfoRole;

     // The HTML element should not be exposed as an element. That's what the RenderView element does.
     if (node && node->hasTagName(htmlTag))
         return IgnoredRole;

     // There should only be one banner/contentInfo per page. If header/footer are being used within an article or section
     // then it should not be exposed as whole page's banner/contentInfo
     if (node && node->hasTagName(headerTag) && !isDescendantOfElementType(articleTag) && !isDescendantOfElementType(sectionTag))
         return LandmarkBannerRole;
     if (node && node->hasTagName(footerTag) && !isDescendantOfElementType(articleTag) && !isDescendantOfElementType(sectionTag))
         return FooterRole;

     if (m_renderer->isRenderBlockFlow())
         return GroupRole;

     // If the element does not have role, but it has ARIA attributes, accessibility should fallback to exposing it as a group.
     if (supportsARIAAttributes())
         return GroupRole;

     return UnknownRole;
 }

 AccessibilityOrientation AccessibilityRenderObject::orientation() const
 {
     const AtomicString& ariaOrientation = getAttribute(aria_orientationAttr);
     if (equalIgnoringCase(ariaOrientation, "horizontal"))
         return AccessibilityOrientationHorizontal;
     if (equalIgnoringCase(ariaOrientation, "vertical"))
         return AccessibilityOrientationVertical;

     return AccessibilityObject::orientation();
 }

 bool AccessibilityRenderObject::inheritsPresentationalRole() const
 {
     // ARIA states if an item can get focus, it should not be presentational.
     if (canSetFocusAttribute())
         return false;

     // ARIA spec says that when a parent object is presentational, and it has required child elements,
     // those child elements are also presentational. For example, <li> becomes presentational from <ul>.
     // http://www.w3.org/WAI/PF/aria/complete#presentation
     DEFINE_STATIC_LOCAL(HashSet<QualifiedName>, listItemParents, ());

     HashSet<QualifiedName>* possibleParentTagNames = 0;
     switch (roleValue()) {
     case ListItemRole:
     case ListMarkerRole:
         if (listItemParents.isEmpty()) {
             listItemParents.add(ulTag);
             listItemParents.add(olTag);
             listItemParents.add(dlTag);
         }
         possibleParentTagNames = &listItemParents;
         break;
     default:
         break;
     }

     // Not all elements need to check for this, only ones that are required children.
     if (!possibleParentTagNames)
         return false;

     for (AccessibilityObject* parent = parentObject(); parent; parent = parent->parentObject()) {
         if (!parent->isAccessibilityRenderObject())
             continue;

         Node* elementNode = static_cast<AccessibilityRenderObject*>(parent)->node();
         if (!elementNode || !elementNode->isElementNode())
             continue;

         // If native tag of the parent element matches an acceptable name, then return
         // based on its presentational status.
         if (possibleParentTagNames->contains(toElement(elementNode)->tagQName()))
             return parent->roleValue() == PresentationalRole;
     }

     return false;
 }

 bool AccessibilityRenderObject::isPresentationalChildOfAriaRole() const
 {
     // Walk the parent chain looking for a parent that has presentational children
     AccessibilityObject* parent;
     for (parent = parentObject(); parent && !parent->ariaRoleHasPresentationalChildren(); parent = parent->parentObject())
     { }

     return parent;
 }

 bool AccessibilityRenderObject::ariaRoleHasPresentationalChildren() const
 {
     switch (m_ariaRole) {
     case ButtonRole:
     case SliderRole:
     case ImageRole:
     case ProgressIndicatorRole:
     case SpinButtonRole:
     // case SeparatorRole:
         return true;
     default:
         return false;
     }
 }

 bool AccessibilityRenderObject::canSetExpandedAttribute() const
 {
     // An object can be expanded if it aria-expanded is true or false.
     const AtomicString& ariaExpanded = getAttribute(aria_expandedAttr);
     return equalIgnoringCase(ariaExpanded, "true") || equalIgnoringCase(ariaExpanded, "false");
 }

 bool AccessibilityRenderObject::canSetValueAttribute() const
 {

     // In the event of a (Boolean)@readonly and (True/False/Undefined)@aria-readonly
     // value mismatch, the host language native attribute value wins.
     if (isNativeTextControl())
         return !isReadOnly();

     if (isMeter())
         return false;

     if (equalIgnoringCase(getAttribute(aria_readonlyAttr), "true"))
         return false;

     if (equalIgnoringCase(getAttribute(aria_readonlyAttr), "false"))
         return true;

     if (isProgressIndicator() || isSlider())
         return true;

     if (isTextControl() && !isNativeTextControl())
         return true;

     // Any node could be contenteditable, so isReadOnly should be relied upon
     // for this information for all elements.
     return !isReadOnly();
 }

 bool AccessibilityRenderObject::canSetTextRangeAttributes() const
 {
     return isTextControl();
 }

 void AccessibilityRenderObject::textChanged()
 {
     // If this element supports ARIA live regions, or is part of a region with an ARIA editable role,
     // then notify the AT of changes.
     AXObjectCache* cache = axObjectCache();
     for (RenderObject* renderParent = m_renderer; renderParent; renderParent = renderParent->parent()) {
         AccessibilityObject* parent = cache->get(renderParent);
         if (!parent)
             continue;

         if (parent->supportsARIALiveRegion())
             cache->postNotification(renderParent, AXObjectCache::AXLiveRegionChanged, true);

         if (parent->isARIATextControl() && !parent->isNativeTextControl() && !parent->node()->rendererIsEditable())
             cache->postNotification(renderParent, AXObjectCache::AXValueChanged, true);
     }
 }

 void AccessibilityRenderObject::clearChildren()
 {
     AccessibilityObject::clearChildren();
     m_childrenDirty = false;
 }

 void AccessibilityRenderObject::addImageMapChildren()
 {
     RenderBoxModelObject* cssBox = renderBoxModelObject();
     if (!cssBox || !cssBox->isRenderImage())
         return;

     HTMLMapElement* map = toRenderImage(cssBox)->imageMap();
     if (!map)
         return;

     for (auto area = descendantsOfType<HTMLAreaElement>(map).begin(), end = descendantsOfType<HTMLAreaElement>(map).end() ; area != end; ++area) {
         // add an <area> element for this child if it has a link
         if (!area->isLink())
             continue;
         AccessibilityImageMapLink* areaObject = static_cast<AccessibilityImageMapLink*>(axObjectCache()->getOrCreate(ImageMapLinkRole));
         areaObject->setHTMLAreaElement(&*area);
         areaObject->setHTMLMapElement(map);
         areaObject->setParent(this);
         if (!areaObject->accessibilityIsIgnored())
             m_children.append(areaObject);
         else
             axObjectCache()->remove(areaObject->axObjectID());
     }
 }

 void AccessibilityRenderObject::updateChildrenIfNecessary()
 {
     if (needsToUpdateChildren())
         clearChildren();

     AccessibilityObject::updateChildrenIfNecessary();
 }

 void AccessibilityRenderObject::addTextFieldChildren()
 {
     Node* node = this->node();
     if (!node || !isHTMLInputElement(node))
         return;

     HTMLInputElement* input = toHTMLInputElement(node);
     HTMLElement* spinButtonElement = input->innerSpinButtonElement();
     if (!spinButtonElement || !spinButtonElement->isSpinButtonElement())
         return;

     AccessibilitySpinButton* axSpinButton = static_cast<AccessibilitySpinButton*>(axObjectCache()->getOrCreate(SpinButtonRole));
     axSpinButton->setSpinButtonElement(static_cast<SpinButtonElement*>(spinButtonElement));
     axSpinButton->setParent(this);
     m_children.append(axSpinButton);
 }

 bool AccessibilityRenderObject::isSVGImage() const
 {
     return remoteSVGRootElement();
 }

 void AccessibilityRenderObject::detachRemoteSVGRoot()
 {
     if (AccessibilitySVGRoot* root = remoteSVGRootElement())
         root->setParent(0);
 }

 AccessibilitySVGRoot* AccessibilityRenderObject::remoteSVGRootElement() const
 {
 #if ENABLE(SVG)
     if (!m_renderer || !m_renderer->isRenderImage())
         return 0;

     CachedImage* cachedImage = toRenderImage(m_renderer)->cachedImage();
     if (!cachedImage)
         return 0;

     Image* image = cachedImage->image();
     if (!image || !image->isSVGImage())
         return 0;

     SVGImage* svgImage = static_cast<SVGImage*>(image);
     FrameView* frameView = svgImage->frameView();
     if (!frameView)
         return 0;
     Frame& frame = frameView->frame();

     Document* doc = frame.document();
     if (!doc || !doc->isSVGDocument())
         return 0;

     SVGSVGElement* rootElement = toSVGDocument(doc)->rootElement();
     if (!rootElement)
         return 0;
     RenderObject* rendererRoot = rootElement->renderer();
     if (!rendererRoot)
         return 0;

     AccessibilityObject* rootSVGObject = frame.document()->axObjectCache()->getOrCreate(rendererRoot);

     // In order to connect the AX hierarchy from the SVG root element from the loaded resource
     // the parent must be set, because there's no other way to get back to who created the image.
     ASSERT(rootSVGObject && rootSVGObject->isAccessibilitySVGRoot());
     if (!rootSVGObject->isAccessibilitySVGRoot())
         return 0;

     return toAccessibilitySVGRoot(rootSVGObject);
 #else
     return 0;
 #endif
 }

 void AccessibilityRenderObject::addRemoteSVGChildren()
 {
     AccessibilitySVGRoot* root = remoteSVGRootElement();
     if (!root)
         return;

     root->setParent(this);

     if (root->accessibilityIsIgnored()) {
         AccessibilityChildrenVector children = root->children();
         unsigned length = children.size();
         for (unsigned i = 0; i < length; ++i)
             m_children.append(children[i]);
     } else
         m_children.append(root);
 }

 void AccessibilityRenderObject::addCanvasChildren()
 {
     // Add the unrendered canvas children as AX nodes, unless we're not using a canvas renderer
     // because JS is disabled for example.
     if (!node() || !node()->hasTagName(canvasTag) || (renderer() && !renderer()->isCanvas()))
         return;

     // If it's a canvas, it won't have rendered children, but it might have accessible fallback content.
     // Clear m_haveChildren because AccessibilityNodeObject::addChildren will expect it to be false.
     ASSERT(!m_children.size());
     m_haveChildren = false;
     AccessibilityNodeObject::addChildren();
 }

 void AccessibilityRenderObject::addAttachmentChildren()
 {
     if (!isAttachment())
         return;

     // FrameView's need to be inserted into the AX hierarchy when encountered.
     Widget* widget = widgetForAttachmentView();
     if (!widget || !widget->isFrameView())
         return;

     AccessibilityObject* axWidget = axObjectCache()->getOrCreate(widget);
     if (!axWidget->accessibilityIsIgnored())
         m_children.append(axWidget);
 }

 #if PLATFORM(MAC)
 void AccessibilityRenderObject::updateAttachmentViewParents()
 {
     // Only the unignored parent should set the attachment parent, because that's what is reflected in the AX
     // hierarchy to the client.
     if (accessibilityIsIgnored())
         return;

     size_t length = m_children.size();
     for (size_t k = 0; k < length; k++) {
         if (m_children[k]->isAttachment())
             m_children[k]->overrideAttachmentParent(this);
     }
 }
 #endif

 // Hidden children are those that are not rendered or visible, but are specifically marked as aria-hidden=false,
 // meaning that they should be exposed to the AX hierarchy.
 void AccessibilityRenderObject::addHiddenChildren()
 {
     Node* node = this->node();
     if (!node)
         return;

     // First do a quick run through to determine if we have any hidden nodes (most often we will not).
     // If we do have hidden nodes, we need to determine where to insert them so they match DOM order as close as possible.
     bool shouldInsertHiddenNodes = false;
     for (Node* child = node->firstChild(); child; child = child->nextSibling()) {
         if (!child->renderer() && isNodeAriaVisible(child)) {
             shouldInsertHiddenNodes = true;
             break;
         }
     }

     if (!shouldInsertHiddenNodes)
         return;

     // Iterate through all of the children, including those that may have already been added, and
     // try to insert hidden nodes in the correct place in the DOM order.
     unsigned insertionIndex = 0;
     for (Node* child = node->firstChild(); child; child = child->nextSibling()) {
         if (child->renderer()) {
             // Find out where the last render sibling is located within m_children.
             AccessibilityObject* childObject = axObjectCache()->get(child->renderer());
             if (childObject && childObject->accessibilityIsIgnored()) {
                 AccessibilityChildrenVector children = childObject->children();
                 if (children.size())
                     childObject = children.last().get();
                 else
                     childObject = 0;
             }

             if (childObject)
                 insertionIndex = m_children.find(childObject) + 1;
             continue;
         }

         if (!isNodeAriaVisible(child))
             continue;

         unsigned previousSize = m_children.size();
         if (insertionIndex > previousSize)
             insertionIndex = previousSize;

         insertChild(axObjectCache()->getOrCreate(child), insertionIndex);
         insertionIndex += (m_children.size() - previousSize);
     }
 }

 void AccessibilityRenderObject::addChildren()
 {
     // If the need to add more children in addition to existing children arises,
     // childrenChanged should have been called, leaving the object with no children.
     ASSERT(!m_haveChildren);

     m_haveChildren = true;

     if (!canHaveChildren())
         return;

     for (RefPtr<AccessibilityObject> obj = firstChild(); obj; obj = obj->nextSibling())
         addChild(obj.get());

     addHiddenChildren();
     addAttachmentChildren();
     addImageMapChildren();
     addTextFieldChildren();
     addCanvasChildren();
     addRemoteSVGChildren();

 #if PLATFORM(MAC)
     updateAttachmentViewParents();
 #endif
 }

 bool AccessibilityRenderObject::canHaveChildren() const
 {
     if (!m_renderer)
         return false;

     return AccessibilityNodeObject::canHaveChildren();
 }

 const AtomicString& AccessibilityRenderObject::ariaLiveRegionStatus() const
 {
     DEFINE_STATIC_LOCAL(const AtomicString, liveRegionStatusAssertive, ("assertive", AtomicString::ConstructFromLiteral));
     DEFINE_STATIC_LOCAL(const AtomicString, liveRegionStatusPolite, ("polite", AtomicString::ConstructFromLiteral));
     DEFINE_STATIC_LOCAL(const AtomicString, liveRegionStatusOff, ("off", AtomicString::ConstructFromLiteral));

     const AtomicString& liveRegionStatus = getAttribute(aria_liveAttr);
     // These roles have implicit live region status.
     if (liveRegionStatus.isEmpty()) {
         switch (roleValue()) {
         case ApplicationAlertDialogRole:
         case ApplicationAlertRole:
             return liveRegionStatusAssertive;
         case ApplicationLogRole:
         case ApplicationStatusRole:
             return liveRegionStatusPolite;
         case ApplicationTimerRole:
         case ApplicationMarqueeRole:
             return liveRegionStatusOff;
         default:
             break;
         }
     }

     return liveRegionStatus;
 }

 const AtomicString& AccessibilityRenderObject::ariaLiveRegionRelevant() const
 {
     DEFINE_STATIC_LOCAL(const AtomicString, defaultLiveRegionRelevant, ("additions text", AtomicString::ConstructFromLiteral));
     const AtomicString& relevant = getAttribute(aria_relevantAttr);

     // Default aria-relevant = "additions text".
     if (relevant.isEmpty())
         return defaultLiveRegionRelevant;

     return relevant;
 }

 bool AccessibilityRenderObject::ariaLiveRegionAtomic() const
 {
     return elementAttributeValue(aria_atomicAttr);
 }

 bool AccessibilityRenderObject::ariaLiveRegionBusy() const
 {
     return elementAttributeValue(aria_busyAttr);
 }

 void AccessibilityRenderObject::ariaSelectedRows(AccessibilityChildrenVector& result)
 {
     // Get all the rows.
     AccessibilityChildrenVector allRows;
     if (isTree())
         ariaTreeRows(allRows);
     else if (isAccessibilityTable() && toAccessibilityTable(this)->supportsSelectedRows())
         allRows = toAccessibilityTable(this)->rows();

     // Determine which rows are selected.
     bool isMulti = isMultiSelectable();

     // Prefer active descendant over aria-selected.
     AccessibilityObject* activeDesc = activeDescendant();
     if (activeDesc && (activeDesc->isTreeItem() || activeDesc->isTableRow())) {
         result.append(activeDesc);
         if (!isMulti)
             return;
     }

     unsigned count = allRows.size();
     for (unsigned k = 0; k < count; ++k) {
         if (allRows[k]->isSelected()) {
             result.append(allRows[k]);
             if (!isMulti)
                 break;
         }
     }
 }

 void AccessibilityRenderObject::ariaListboxSelectedChildren(AccessibilityChildrenVector& result)
 {
     bool isMulti = isMultiSelectable();

     AccessibilityChildrenVector childObjects = children();
     unsigned childrenSize = childObjects.size();
     for (unsigned k = 0; k < childrenSize; ++k) {
         // Every child should have aria-role option, and if so, check for selected attribute/state.
         AccessibilityObject* child = childObjects[k].get();
         if (child->isSelected() && child->ariaRoleAttribute() == ListBoxOptionRole) {
             result.append(child);
             if (!isMulti)
                 return;
         }
     }
 }

 void AccessibilityRenderObject::selectedChildren(AccessibilityChildrenVector& result)
 {
     ASSERT(result.isEmpty());

     // only listboxes should be asked for their selected children.
     AccessibilityRole role = roleValue();
     if (role == ListBoxRole) // native list boxes would be AccessibilityListBoxes, so only check for aria list boxes
         ariaListboxSelectedChildren(result);
     else if (role == TreeRole || role == TreeGridRole || role == TableRole)
         ariaSelectedRows(result);
 }

 void AccessibilityRenderObject::ariaListboxVisibleChildren(AccessibilityChildrenVector& result)
 {
     if (!hasChildren())
         addChildren();

     AccessibilityObject::AccessibilityChildrenVector children = this->children();
     size_t size = children.size();
     for (size_t i = 0; i < size; i++) {
         if (!children[i]->isOffScreen())
             result.append(children[i]);
     }
 }

 void AccessibilityRenderObject::visibleChildren(AccessibilityChildrenVector& result)
 {
     ASSERT(result.isEmpty());

     // only listboxes are asked for their visible children.
     if (ariaRoleAttribute() != ListBoxRole) { // native list boxes would be AccessibilityListBoxes, so only check for aria list boxes
         ASSERT_NOT_REACHED();
         return;
     }
     return ariaListboxVisibleChildren(result);
 }

 void AccessibilityRenderObject::tabChildren(AccessibilityChildrenVector& result)
 {
     ASSERT(roleValue() == TabListRole);

     AccessibilityObject::AccessibilityChildrenVector children = this->children();
     size_t size = children.size();
     for (size_t i = 0; i < size; ++i) {
         if (children[i]->isTabItem())
             result.append(children[i]);
     }
 }

 const String& AccessibilityRenderObject::actionVerb() const
 {
 #if !PLATFORM(IOS)
     // FIXME: Need to add verbs for select elements.
     DEFINE_STATIC_LOCAL(const String, buttonAction, (AXButtonActionVerb()));
     DEFINE_STATIC_LOCAL(const String, textFieldAction, (AXTextFieldActionVerb()));
     DEFINE_STATIC_LOCAL(const String, radioButtonAction, (AXRadioButtonActionVerb()));
     DEFINE_STATIC_LOCAL(const String, checkedCheckBoxAction, (AXCheckedCheckBoxActionVerb()));
     DEFINE_STATIC_LOCAL(const String, uncheckedCheckBoxAction, (AXUncheckedCheckBoxActionVerb()));
     DEFINE_STATIC_LOCAL(const String, linkAction, (AXLinkActionVerb()));

     switch (roleValue()) {
     case ButtonRole:
     case ToggleButtonRole:
         return buttonAction;
     case TextFieldRole:
     case TextAreaRole:
         return textFieldAction;
     case RadioButtonRole:
         return radioButtonAction;
     case CheckBoxRole:
         return isChecked() ? checkedCheckBoxAction : uncheckedCheckBoxAction;
     case LinkRole:
     case WebCoreLinkRole:
         return linkAction;
     default:
         return nullAtom;
     }
 #else
     return nullAtom;
 #endif
 }

 void AccessibilityRenderObject::setAccessibleName(const AtomicString& name)
 {
     // Setting the accessible name can store the value in the DOM
     if (!m_renderer)
         return;

     Node* domNode = 0;
     // For web areas, set the aria-label on the HTML element.
     if (isWebArea())
         domNode = m_renderer->document().documentElement();
     else
         domNode = m_renderer->node();

     if (domNode && domNode->isElementNode())
         toElement(domNode)->setAttribute(aria_labelAttr, name);
 }

 static bool isLinkable(const AccessibilityRenderObject& object)
 {
     if (!object.renderer())
         return false;

     // See https://wiki.mozilla.org/Accessibility/AT-Windows-API for the elements
     // Mozilla considers linkable.
     return object.isLink() || object.isImage() || object.renderer()->isText();
 }

 String AccessibilityRenderObject::stringValueForMSAA() const
 {
     if (isLinkable(*this)) {
         Element* anchor = anchorElement();
         if (anchor && isHTMLAnchorElement(anchor))
             return toHTMLAnchorElement(anchor)->href();
     }

     return stringValue();
 }

 bool AccessibilityRenderObject::isLinked() const
 {
     if (!isLinkable(*this))
         return false;

     Element* anchor = anchorElement();
     if (!anchor || !isHTMLAnchorElement(anchor))
         return false;

     return !toHTMLAnchorElement(anchor)->href().isEmpty();
 }

 bool AccessibilityRenderObject::hasBoldFont() const
 {
     if (!m_renderer)
         return false;

     return m_renderer->style()->fontDescription().weight() >= FontWeightBold;
 }

 bool AccessibilityRenderObject::hasItalicFont() const
 {
     if (!m_renderer)
         return false;

     return m_renderer->style()->fontDescription().italic() == FontItalicOn;
 }

 bool AccessibilityRenderObject::hasPlainText() const
 {
     if (!m_renderer)
         return false;

     RenderStyle* style = m_renderer->style();

     return style->fontDescription().weight() == FontWeightNormal
         && style->fontDescription().italic() == FontItalicOff
         && style->textDecorationsInEffect() == TextDecorationNone;
 }

 bool AccessibilityRenderObject::hasSameFont(RenderObject* renderer) const
 {
     if (!m_renderer || !renderer)
         return false;

     return m_renderer->style()->fontDescription().families() == renderer->style()->fontDescription().families();
 }

 bool AccessibilityRenderObject::hasSameFontColor(RenderObject* renderer) const
 {
     if (!m_renderer || !renderer)
         return false;

     return m_renderer->style()->visitedDependentColor(CSSPropertyColor) == renderer->style()->visitedDependentColor(CSSPropertyColor);
 }

 bool AccessibilityRenderObject::hasSameStyle(RenderObject* renderer) const
 {
     if (!m_renderer || !renderer)
         return false;

     return m_renderer->style() == renderer->style();
 }

 bool AccessibilityRenderObject::hasUnderline() const
 {
     if (!m_renderer)
         return false;

     return m_renderer->style()->textDecorationsInEffect() & TextDecorationUnderline;
 }

 String AccessibilityRenderObject::nameForMSAA() const
 {
     if (m_renderer && m_renderer->isText())
         return textUnderElement();

     return title();
 }

 static bool shouldReturnTagNameAsRoleForMSAA(const Element& element)
 {
     // See "document structure",
     // https://wiki.mozilla.org/Accessibility/AT-Windows-API
     // FIXME: Add the other tag names that should be returned as the role.
     return element.hasTagName(h1Tag) || element.hasTagName(h2Tag)
         || element.hasTagName(h3Tag) || element.hasTagName(h4Tag)
         || element.hasTagName(h5Tag) || element.hasTagName(h6Tag);
 }

 String AccessibilityRenderObject::stringRoleForMSAA() const
 {
     if (!m_renderer)
         return String();

     Node* node = m_renderer->node();
     if (!node || !node->isElementNode())
         return String();

     Element* element = toElement(node);
     if (!shouldReturnTagNameAsRoleForMSAA(*element))
         return String();

     return element->tagName();
 }

 String AccessibilityRenderObject::positionalDescriptionForMSAA() const
 {
     // See "positional descriptions",
     // https://wiki.mozilla.org/Accessibility/AT-Windows-API
     if (isHeading())
         return "L" + String::number(headingLevel());

     // FIXME: Add positional descriptions for other elements.
     return String();
 }

 String AccessibilityRenderObject::descriptionForMSAA() const
 {
     String description = positionalDescriptionForMSAA();
     if (!description.isEmpty())
         return description;

     description = accessibilityDescription();
     if (!description.isEmpty()) {
         // From the Mozilla MSAA implementation:
         // "Signal to screen readers that this description is speakable and is not
         // a formatted positional information description. Don't localize the
         // 'Description: ' part of this string, it will be parsed out by assistive
         // technologies."
         return "Description: " + description;
     }

     return String();
 }

 static AccessibilityRole msaaRoleForRenderer(const RenderObject* renderer)
 {
     if (!renderer)
         return UnknownRole;

     if (renderer->isText())
         return EditableTextRole;

     if (renderer->isBoxModelObject() && toRenderBoxModelObject(renderer)->isListItem())
         return ListItemRole;

     return UnknownRole;
 }

 AccessibilityRole AccessibilityRenderObject::roleValueForMSAA() const
 {
     if (m_roleForMSAA != UnknownRole)
         return m_roleForMSAA;

     m_roleForMSAA = msaaRoleForRenderer(m_renderer);

     if (m_roleForMSAA == UnknownRole)
         m_roleForMSAA = roleValue();

     return m_roleForMSAA;
 }

 String AccessibilityRenderObject::passwordFieldValue() const
 {
 #if PLATFORM(GTK)
     ASSERT(isPasswordField());

     // Look for the RenderText object in the RenderObject tree for this input field.
     RenderObject* renderer = node()->renderer();
     while (renderer && !renderer->isText())
         renderer = renderer->firstChild();

     if (!renderer || !renderer->isText())
         return String();

     // Return the text that is actually being rendered in the input field.
     return static_cast<RenderText*>(renderer)->textWithoutTranscoding();
 #else
     // It seems only GTK is interested in this at the moment.
     return String();
 #endif
 }

 ScrollableArea* AccessibilityRenderObject::getScrollableAreaIfScrollable() const
 {
     // If the parent is a scroll view, then this object isn't really scrollable, the parent ScrollView should handle the scrolling.
     if (parentObject() && parentObject()->isAccessibilityScrollView())
         return 0;

     if (!m_renderer || !m_renderer->isBox())
         return 0;

     RenderBox* box = toRenderBox(m_renderer);
     if (!box->canBeScrolledAndHasScrollableArea())
         return 0;

     return box->layer();
 }

 void AccessibilityRenderObject::scrollTo(const IntPoint& point) const
 {
     if (!m_renderer || !m_renderer->isBox())
         return;

     RenderBox* box = toRenderBox(m_renderer);
     if (!box->canBeScrolledAndHasScrollableArea())
         return;

     RenderLayer* layer = box->layer();
     layer->scrollToOffset(toIntSize(point), RenderLayer::ScrollOffsetClamped);
 }

 #if ENABLE(MATHML)
 bool AccessibilityRenderObject::isMathElement() const
 {
     Node* node = this->node();
     if (!m_renderer || !node)
         return false;

     return node->isElementNode() && toElement(node)->isMathMLElement();
 }

 bool AccessibilityRenderObject::isMathFraction() const
 {
     if (!m_renderer || !m_renderer->isRenderMathMLBlock())
         return false;

     return toRenderMathMLBlock(m_renderer)->isRenderMathMLFraction();
 }

 bool AccessibilityRenderObject::isMathFenced() const
 {
     if (!m_renderer || !m_renderer->isRenderMathMLBlock())
         return false;

     return toRenderMathMLBlock(m_renderer)->isRenderMathMLFenced();
 }

 bool AccessibilityRenderObject::isMathSubscriptSuperscript() const
 {
     if (!m_renderer || !m_renderer->isRenderMathMLBlock())
         return false;

     return toRenderMathMLBlock(m_renderer)->isRenderMathMLScripts() && !isMathMultiscript();
 }

 bool AccessibilityRenderObject::isMathRow() const
 {
     if (!m_renderer || !m_renderer->isRenderMathMLBlock())
         return false;

     return toRenderMathMLBlock(m_renderer)->isRenderMathMLRow();
 }

 bool AccessibilityRenderObject::isMathUnderOver() const
 {
     if (!m_renderer || !m_renderer->isRenderMathMLBlock())
         return false;

     return toRenderMathMLBlock(m_renderer)->isRenderMathMLUnderOver();
 }

 bool AccessibilityRenderObject::isMathSquareRoot() const
 {
     if (!m_renderer || !m_renderer->isRenderMathMLBlock())
         return false;

     return toRenderMathMLBlock(m_renderer)->isRenderMathMLSquareRoot();
 }

 bool AccessibilityRenderObject::isMathRoot() const
 {
     if (!m_renderer || !m_renderer->isRenderMathMLBlock())
         return false;

     return toRenderMathMLBlock(m_renderer)->isRenderMathMLRoot();
 }

 bool AccessibilityRenderObject::isMathOperator() const
 {
     if (!m_renderer || !m_renderer->isRenderMathMLBlock())
         return false;

     // Ensure that this is actually a render MathML operator because
     // MathML will create MathMLBlocks and use the original node as the node
     // of this new block that is not tied to the DOM.
     if (!toRenderMathMLBlock(m_renderer)->isRenderMathMLOperator())
         return false;

     return isMathElement() && node()->hasTagName(MathMLNames::moTag);
 }

 bool AccessibilityRenderObject::isMathFenceOperator() const
 {
     if (!m_renderer || !m_renderer->isRenderMathMLBlock())
         return false;

     if (!toRenderMathMLBlock(m_renderer)->isRenderMathMLOperator())
         return false;

     RenderMathMLOperator* mathOperator = toRenderMathMLOperator(toRenderMathMLBlock(m_renderer));
     return mathOperator->operatorType() == RenderMathMLOperator::Fence;
 }

 bool AccessibilityRenderObject::isMathSeparatorOperator() const
 {
     if (!m_renderer || !m_renderer->isRenderMathMLBlock())
         return false;

     if (!toRenderMathMLBlock(m_renderer)->isRenderMathMLOperator())
         return false;

     RenderMathMLOperator* mathOperator = toRenderMathMLOperator(toRenderMathMLBlock(m_renderer));
     return mathOperator->operatorType() == RenderMathMLOperator::Separator;
 }

 bool AccessibilityRenderObject::isMathText() const
 {
     return node() && node()->hasTagName(MathMLNames::mtextTag);
 }

 bool AccessibilityRenderObject::isMathNumber() const
 {
     return node() && node()->hasTagName(MathMLNames::mnTag);
 }

 bool AccessibilityRenderObject::isMathIdentifier() const
 {
     return node() && node()->hasTagName(MathMLNames::miTag);
 }

 bool AccessibilityRenderObject::isMathMultiscript() const
 {
     return node() && node()->hasTagName(MathMLNames::mmultiscriptsTag);
 }

 bool AccessibilityRenderObject::isMathTable() const
 {
     return node() && node()->hasTagName(MathMLNames::mtableTag);
 }

 bool AccessibilityRenderObject::isMathTableRow() const
 {
     return node() && node()->hasTagName(MathMLNames::mtrTag);
 }

 bool AccessibilityRenderObject::isMathTableCell() const
 {
     return node() && node()->hasTagName(MathMLNames::mtdTag);
 }

 bool AccessibilityRenderObject::isIgnoredElementWithinMathTree() const
 {
     if (!m_renderer)
         return true;

     // Ignore items that were created for layout purposes only.
     if (m_renderer->isRenderMathMLBlock() && toRenderMathMLBlock(m_renderer)->ignoreInAccessibilityTree())
         return true;

     // Ignore anonymous renderers inside math blocks.
     if (m_renderer->isAnonymous()) {
         for (AccessibilityObject* parent = parentObject(); parent; parent = parent->parentObject()) {
             if (parent->isMathElement())
                 return true;
         }
     }

     // Only math elements that we explicitly recognize should be included
     // We don't want things like <mstyle> to appear in the tree.
     if (isMathElement()) {
         if (isMathFraction() || isMathFenced() || isMathSubscriptSuperscript() || isMathRow()
             || isMathUnderOver() || isMathRoot() || isMathText() || isMathNumber()
             || isMathOperator() || isMathFenceOperator() || isMathSeparatorOperator()
             || isMathIdentifier() || isMathTable() || isMathTableRow() || isMathTableCell() || isMathMultiscript())
             return false;
         return true;
     }

     return false;
 }

 AccessibilityObject* AccessibilityRenderObject::mathRadicandObject()
 {
     if (!isMathRoot())
         return 0;

     AccessibilityObject::AccessibilityChildrenVector children = this->children();
     if (children.size() < 1)
         return 0;

     // The radicand is the value being rooted and must be listed first.
     return children[0].get();
 }

 AccessibilityObject* AccessibilityRenderObject::mathRootIndexObject()
 {
     if (!isMathRoot())
         return 0;

     AccessibilityObject::AccessibilityChildrenVector children = this->children();
     if (children.size() != 2)
         return 0;

     // The index in a root is the value which determines if it's a square, cube, etc, root
     // and must be listed second.
     return children[1].get();
 }

 AccessibilityObject* AccessibilityRenderObject::mathNumeratorObject()
 {
     if (!isMathFraction())
         return 0;

     AccessibilityObject::AccessibilityChildrenVector children = this->children();
     if (children.size() != 2)
         return 0;

     return children[0].get();
 }

 AccessibilityObject* AccessibilityRenderObject::mathDenominatorObject()
 {
     if (!isMathFraction())
         return 0;

     AccessibilityObject::AccessibilityChildrenVector children = this->children();
     if (children.size() != 2)
         return 0;

     return children[1].get();
 }

 AccessibilityObject* AccessibilityRenderObject::mathUnderObject()
 {
     if (!isMathUnderOver() || !node())
         return 0;

     AccessibilityChildrenVector children = this->children();
     if (children.size() < 2)
         return 0;

     if (node()->hasTagName(MathMLNames::munderTag) || node()->hasTagName(MathMLNames::munderoverTag))
         return children[1].get();

     return 0;
 }

 AccessibilityObject* AccessibilityRenderObject::mathOverObject()
 {
     if (!isMathUnderOver() || !node())
         return 0;

     AccessibilityChildrenVector children = this->children();
     if (children.size() < 2)
         return 0;

     if (node()->hasTagName(MathMLNames::moverTag))
         return children[1].get();
     if (node()->hasTagName(MathMLNames::munderoverTag))
         return children[2].get();

     return 0;
 }

 AccessibilityObject* AccessibilityRenderObject::mathBaseObject()
 {
     if (!isMathSubscriptSuperscript() && !isMathUnderOver() && !isMathMultiscript())
         return 0;

     AccessibilityChildrenVector children = this->children();
     // The base object in question is always the first child.
     if (children.size() > 0)
         return children[0].get();

     return 0;
 }

 AccessibilityObject* AccessibilityRenderObject::mathSubscriptObject()
 {
     if (!isMathSubscriptSuperscript() || !node())
         return 0;

     AccessibilityChildrenVector children = this->children();
     if (children.size() < 2)
         return 0;

     if (node()->hasTagName(MathMLNames::msubTag) || node()->hasTagName(MathMLNames::msubsupTag))
         return children[1].get();

     return 0;
 }

 AccessibilityObject* AccessibilityRenderObject::mathSuperscriptObject()
 {
     if (!isMathSubscriptSuperscript() || !node())
         return 0;

     AccessibilityChildrenVector children = this->children();
     unsigned count = children.size();

     if (count >= 2 && node()->hasTagName(MathMLNames::msupTag))
         return children[1].get();

     if (count >= 3 && node()->hasTagName(MathMLNames::msubsupTag))
         return children[2].get();

     return 0;
 }

 String AccessibilityRenderObject::mathFencedOpenString() const
 {
     if (!isMathFenced())
         return String();

     return getAttribute(MathMLNames::openAttr);
 }

 String AccessibilityRenderObject::mathFencedCloseString() const
 {
     if (!isMathFenced())
         return String();

     return getAttribute(MathMLNames::closeAttr);
 }

 void AccessibilityRenderObject::mathPrescripts(AccessibilityMathMultiscriptPairs& prescripts)
 {
     if (!isMathMultiscript() || !node())
         return;

     bool foundPrescript = false;
     pair<AccessibilityObject*, AccessibilityObject*> prescriptPair;
     for (Node* child = node()->firstChild(); child; child = child->nextSibling()) {
         if (foundPrescript) {
             AccessibilityObject* axChild = axObjectCache()->getOrCreate(child);
             if (axChild && axChild->isMathElement()) {
                 if (!prescriptPair.first)
                     prescriptPair.first = axChild;
                 else {
                     prescriptPair.second = axChild;
                     prescripts.append(prescriptPair);
                     prescriptPair.first = 0;
                     prescriptPair.second = 0;
                 }
             }
         } else if (child->hasTagName(MathMLNames::mprescriptsTag))
             foundPrescript = true;
     }

     // Handle the odd number of pre scripts case.
     if (prescriptPair.first)
         prescripts.append(prescriptPair);
 }

 void AccessibilityRenderObject::mathPostscripts(AccessibilityMathMultiscriptPairs& postscripts)
 {
     if (!isMathMultiscript() || !node())
         return;

     // In Multiscripts, the post-script elements start after the first element (which is the base)
     // and continue until a <mprescripts> tag is found
     pair<AccessibilityObject*, AccessibilityObject*> postscriptPair;
     bool foundBaseElement = false;
     for (Node* child = node()->firstChild(); child; child = child->nextSibling()) {
         if (child->hasTagName(MathMLNames::mprescriptsTag))
             break;

         AccessibilityObject* axChild = axObjectCache()->getOrCreate(child);
         if (axChild && axChild->isMathElement()) {
             if (!foundBaseElement)
                 foundBaseElement = true;
             else if (!postscriptPair.first)
                 postscriptPair.first = axChild;
             else {
                 postscriptPair.second = axChild;
                 postscripts.append(postscriptPair);
                 postscriptPair.first = 0;
                 postscriptPair.second = 0;
             }
         }
     }

     // Handle the odd number of post scripts case.
     if (postscriptPair.first)
         postscripts.append(postscriptPair);
 }

 int AccessibilityRenderObject::mathLineThickness() const
 {
     if (!isMathFraction())
         return -1;

     return toRenderMathMLFraction(m_renderer)->lineThickness();
 }

 #endif

 } // namespace WebCore