Source/WebCore/dom/Element.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */

 #include "config.h"
 #include "Element.h"

 #include "AXObjectCache.h"
 #include "Attr.h"
 #include "CSSParser.h"
 #include "CSSSelectorList.h"
 #include "ClassList.h"
 #include "ClientRect.h"
 #include "ClientRectList.h"
 #include "DOMTokenList.h"
 #include "DatasetDOMStringMap.h"
 #include "Document.h"
 #include "DocumentFragment.h"
 #include "ElementRareData.h"
 #include "ExceptionCode.h"
 #include "FlowThreadController.h"
 #include "FocusController.h"
 #include "Frame.h"
 #include "FrameView.h"
 #include "HTMLCollection.h"
 #include "HTMLDocument.h"
 #include "HTMLElement.h"
 #include "HTMLFormCollection.h"
 #include "HTMLFrameOwnerElement.h"
 #include "HTMLLabelElement.h"
 #include "HTMLNames.h"
 #include "HTMLOptionsCollection.h"
 #include "HTMLParserIdioms.h"
 #include "HTMLTableRowsCollection.h"
 #include "InspectorInstrumentation.h"
 #include "MutationObserverInterestGroup.h"
 #include "MutationRecord.h"
 #include "NamedNodeMap.h"
 #include "NodeList.h"
 #include "NodeRenderStyle.h"
 #include "NodeRenderingContext.h"
 #include "Page.h"
 #include "PointerLockController.h"
 #include "RenderRegion.h"
 #include "RenderView.h"
 #include "RenderWidget.h"
 #include "SelectorQuery.h"
 #include "Settings.h"
 #include "ShadowRoot.h"
 #include "StyleResolver.h"
 #include "Text.h"
 #include "TextIterator.h"
 #include "UndoManager.h"
 #include "VoidCallback.h"
 #include "WebCoreMemoryInstrumentation.h"
 #include "WebKitAnimationList.h"
 #include "XMLNSNames.h"
 #include "XMLNames.h"
 #include "htmlediting.h"
 #include <wtf/BitVector.h>
 #include <wtf/text/CString.h>

 #if ENABLE(SVG)
 #include "SVGElement.h"
 #include "SVGNames.h"
 #endif

 namespace WebCore {

 using namespace HTMLNames;
 using namespace XMLNames;

 class StyleResolverParentPusher {
 public:
     StyleResolverParentPusher(Element* parent)
         : m_parent(parent)
         , m_pushedStyleResolver(0)
     {
     }
     void push()
     {
         if (m_pushedStyleResolver)
             return;
         m_pushedStyleResolver = m_parent->document()->styleResolver();
         m_pushedStyleResolver->pushParentElement(m_parent);
     }
     ~StyleResolverParentPusher()
     {

         if (!m_pushedStyleResolver)
             return;

         // This tells us that our pushed style selector is in a bad state,
         // so we should just bail out in that scenario.
         ASSERT(m_pushedStyleResolver == m_parent->document()->styleResolver());
         if (m_pushedStyleResolver != m_parent->document()->styleResolver())
             return;

         m_pushedStyleResolver->popParentElement(m_parent);
     }

 private:
     Element* m_parent;
     StyleResolver* m_pushedStyleResolver;
 };

 PassRefPtr<Element> Element::create(const QualifiedName& tagName, Document* document)
 {
     return adoptRef(new Element(tagName, document, CreateElement));
 }

 Element::~Element()
 {
 #ifndef NDEBUG
     if (document() && document()->renderer()) {
         // When the document is not destroyed, an element that was part of a named flow
         // content nodes should have been removed from the content nodes collection
         // and the inNamedFlow flag reset.
         ASSERT(!inNamedFlow());
     }
 #endif

     if (ElementShadow* elementShadow = shadow()) {
         elementShadow->removeAllShadowRoots();
         elementRareData()->m_shadow.clear();
     }

     if (hasAttrList()) {
         ASSERT(m_attributeData);
         m_attributeData->detachAttrObjectsFromElement(this);
     }
 }

 inline ElementRareData* Element::elementRareData() const
 {
     ASSERT(hasRareData());
     return static_cast<ElementRareData*>(NodeRareData::rareDataFromMap(this));
 }

 inline ElementRareData* Element::ensureElementRareData()
 {
     return static_cast<ElementRareData*>(ensureRareData());
 }

 OwnPtr<NodeRareData> Element::createRareData()
 {
     return adoptPtr(new ElementRareData);
 }

 DEFINE_VIRTUAL_ATTRIBUTE_EVENT_LISTENER(Element, blur);
 DEFINE_VIRTUAL_ATTRIBUTE_EVENT_LISTENER(Element, error);
 DEFINE_VIRTUAL_ATTRIBUTE_EVENT_LISTENER(Element, focus);
 DEFINE_VIRTUAL_ATTRIBUTE_EVENT_LISTENER(Element, load);

 PassRefPtr<Node> Element::cloneNode(bool deep)
 {
     return deep ? cloneElementWithChildren() : cloneElementWithoutChildren();
 }

 PassRefPtr<Element> Element::cloneElementWithChildren()
 {
     RefPtr<Element> clone = cloneElementWithoutChildren();
     cloneChildNodes(clone.get());
     return clone.release();
 }

 PassRefPtr<Element> Element::cloneElementWithoutChildren()
 {
     RefPtr<Element> clone = cloneElementWithoutAttributesAndChildren();
     // This will catch HTML elements in the wrong namespace that are not correctly copied.
     // This is a sanity check as HTML overloads some of the DOM methods.
     ASSERT(isHTMLElement() == clone->isHTMLElement());

     clone->cloneDataFromElement(*this);
     return clone.release();
 }

 PassRefPtr<Element> Element::cloneElementWithoutAttributesAndChildren()
 {
     return document()->createElement(tagQName(), false);
 }

 PassRefPtr<Attr> Element::detachAttribute(size_t index)
 {
     ASSERT(attributeData());

     const Attribute* attribute = attributeData()->attributeItem(index);
     ASSERT(attribute);

     RefPtr<Attr> attr = attrIfExists(attribute->name());
     if (attr)
         attr->detachFromElementWithValue(attribute->value());
     else
         attr = Attr::create(document(), attribute->name(), attribute->value());

     removeAttributeInternal(index, NotInSynchronizationOfLazyAttribute);
     return attr.release();
 }

 void Element::removeAttribute(const QualifiedName& name)
 {
     if (!attributeData())
         return;

     size_t index = attributeData()->getAttributeItemIndex(name);
     if (index == notFound)
         return;

     removeAttributeInternal(index, NotInSynchronizationOfLazyAttribute);
 }

 void Element::setBooleanAttribute(const QualifiedName& name, bool value)
 {
     if (value)
         setAttribute(name, emptyAtom);
     else
         removeAttribute(name);
 }

 NamedNodeMap* Element::attributes() const
 {
     ensureUpdatedAttributeData();
     ElementRareData* rareData = const_cast<Element*>(this)->ensureElementRareData();
     if (NamedNodeMap* attributeMap = rareData->m_attributeMap.get())
         return attributeMap;

     rareData->m_attributeMap = NamedNodeMap::create(const_cast<Element*>(this));
     return rareData->m_attributeMap.get();
 }

 Node::NodeType Element::nodeType() const
 {
     return ELEMENT_NODE;
 }

 bool Element::hasAttribute(const QualifiedName& name) const
 {
     return hasAttributeNS(name.namespaceURI(), name.localName());
 }

 const AtomicString& Element::getAttribute(const QualifiedName& name) const
 {
     if (UNLIKELY(name == styleAttr) && !isStyleAttributeValid())
         updateStyleAttribute();

 #if ENABLE(SVG)
     if (UNLIKELY(!areSVGAttributesValid()))
         updateAnimatedSVGAttribute(name);
 #endif

     if (attributeData()) {
         if (const Attribute* attribute = getAttributeItem(name))
             return attribute->value();
     }
     return nullAtom;
 }

 void Element::scrollIntoView(bool alignToTop)
 {
     document()->updateLayoutIgnorePendingStylesheets();

     if (!renderer())
         return;

     LayoutRect bounds = boundingBox();
     // Align to the top / bottom and to the closest edge.
     if (alignToTop)
         renderer()->scrollRectToVisible(bounds, ScrollAlignment::alignToEdgeIfNeeded, ScrollAlignment::alignTopAlways);
     else
         renderer()->scrollRectToVisible(bounds, ScrollAlignment::alignToEdgeIfNeeded, ScrollAlignment::alignBottomAlways);
 }

 void Element::scrollIntoViewIfNeeded(bool centerIfNeeded)
 {
     document()->updateLayoutIgnorePendingStylesheets();

     if (!renderer())
         return;

     LayoutRect bounds = boundingBox();
     if (centerIfNeeded)
         renderer()->scrollRectToVisible(bounds, ScrollAlignment::alignCenterIfNeeded, ScrollAlignment::alignCenterIfNeeded);
     else
         renderer()->scrollRectToVisible(bounds, ScrollAlignment::alignToEdgeIfNeeded, ScrollAlignment::alignToEdgeIfNeeded);
 }

 void Element::scrollByUnits(int units, ScrollGranularity granularity)
 {
     document()->updateLayoutIgnorePendingStylesheets();

     if (!renderer())
         return;

     if (!renderer()->hasOverflowClip())
         return;

     ScrollDirection direction = ScrollDown;
     if (units < 0) {
         direction = ScrollUp;
         units = -units;
     }
     Node* stopNode = this;
     toRenderBox(renderer())->scroll(direction, granularity, units, &stopNode);
 }

 void Element::scrollByLines(int lines)
 {
     scrollByUnits(lines, ScrollByLine);
 }

 void Element::scrollByPages(int pages)
 {
     scrollByUnits(pages, ScrollByPage);
 }

 static float localZoomForRenderer(RenderObject* renderer)
 {
     // FIXME: This does the wrong thing if two opposing zooms are in effect and canceled each
     // other out, but the alternative is that we'd have to crawl up the whole render tree every
     // time (or store an additional bit in the RenderStyle to indicate that a zoom was specified).
     float zoomFactor = 1;
     if (renderer->style()->effectiveZoom() != 1) {
         // Need to find the nearest enclosing RenderObject that set up
         // a differing zoom, and then we divide our result by it to eliminate the zoom.
         RenderObject* prev = renderer;
         for (RenderObject* curr = prev->parent(); curr; curr = curr->parent()) {
             if (curr->style()->effectiveZoom() != prev->style()->effectiveZoom()) {
                 zoomFactor = prev->style()->zoom();
                 break;
             }
             prev = curr;
         }
         if (prev->isRenderView())
             zoomFactor = prev->style()->zoom();
     }
     return zoomFactor;
 }

 static int adjustForLocalZoom(LayoutUnit value, RenderObject* renderer)
 {
     float zoomFactor = localZoomForRenderer(renderer);
     if (zoomFactor == 1)
         return value;
 #if ENABLE(SUBPIXEL_LAYOUT)
     return lroundf(value / zoomFactor);
 #else
     // Needed because computeLengthInt truncates (rather than rounds) when scaling up.
     if (zoomFactor > 1)
         value++;
     return static_cast<int>(value / zoomFactor);
 #endif
 }

 int Element::offsetLeft()
 {
     document()->updateLayoutIgnorePendingStylesheets();
     if (RenderBoxModelObject* renderer = renderBoxModelObject())
         return adjustForLocalZoom(renderer->pixelSnappedOffsetLeft(), renderer);
     return 0;
 }

 int Element::offsetTop()
 {
     document()->updateLayoutIgnorePendingStylesheets();
     if (RenderBoxModelObject* renderer = renderBoxModelObject())
         return adjustForLocalZoom(renderer->pixelSnappedOffsetTop(), renderer);
     return 0;
 }

 int Element::offsetWidth()
 {
     document()->updateLayoutIgnorePendingStylesheets();
     if (RenderBoxModelObject* renderer = renderBoxModelObject())
         return adjustForAbsoluteZoom(renderer->pixelSnappedOffsetWidth(), renderer);
     return 0;
 }

 int Element::offsetHeight()
 {
     document()->updateLayoutIgnorePendingStylesheets();
     if (RenderBoxModelObject* renderer = renderBoxModelObject())
         return adjustForAbsoluteZoom(renderer->pixelSnappedOffsetHeight(), renderer);
     return 0;
 }

 Element* Element::offsetParent()
 {
     document()->updateLayoutIgnorePendingStylesheets();
     if (RenderObject* rend = renderer())
         if (RenderObject* offsetParent = rend->offsetParent())
             return static_cast<Element*>(offsetParent->node());
     return 0;
 }

 int Element::clientLeft()
 {
     document()->updateLayoutIgnorePendingStylesheets();

     if (RenderBox* renderer = renderBox())
         return adjustForAbsoluteZoom(roundToInt(renderer->clientLeft()), renderer);
     return 0;
 }

 int Element::clientTop()
 {
     document()->updateLayoutIgnorePendingStylesheets();

     if (RenderBox* renderer = renderBox())
         return adjustForAbsoluteZoom(roundToInt(renderer->clientTop()), renderer);
     return 0;
 }

 int Element::clientWidth()
 {
     document()->updateLayoutIgnorePendingStylesheets();

     // When in strict mode, clientWidth for the document element should return the width of the containing frame.
     // When in quirks mode, clientWidth for the body element should return the width of the containing frame.
     bool inQuirksMode = document()->inQuirksMode();
     if ((!inQuirksMode && document()->documentElement() == this) ||
         (inQuirksMode && isHTMLElement() && document()->body() == this)) {
         if (FrameView* view = document()->view()) {
             if (RenderView* renderView = document()->renderView())
                 return adjustForAbsoluteZoom(view->layoutWidth(), renderView);
         }
     }

     if (RenderBox* renderer = renderBox())
         return adjustForAbsoluteZoom(renderer->pixelSnappedClientWidth(), renderer);
     return 0;
 }

 int Element::clientHeight()
 {
     document()->updateLayoutIgnorePendingStylesheets();

     // When in strict mode, clientHeight for the document element should return the height of the containing frame.
     // When in quirks mode, clientHeight for the body element should return the height of the containing frame.
     bool inQuirksMode = document()->inQuirksMode();

     if ((!inQuirksMode && document()->documentElement() == this) ||
         (inQuirksMode && isHTMLElement() && document()->body() == this)) {
         if (FrameView* view = document()->view()) {
             if (RenderView* renderView = document()->renderView())
                 return adjustForAbsoluteZoom(view->layoutHeight(), renderView);
         }
     }

     if (RenderBox* renderer = renderBox())
         return adjustForAbsoluteZoom(renderer->pixelSnappedClientHeight(), renderer);
     return 0;
 }

 int Element::scrollLeft()
 {
     document()->updateLayoutIgnorePendingStylesheets();
     if (RenderBox* rend = renderBox())
         return adjustForAbsoluteZoom(rend->scrollLeft(), rend);
     return 0;
 }

 int Element::scrollTop()
 {
     document()->updateLayoutIgnorePendingStylesheets();
     if (RenderBox* rend = renderBox())
         return adjustForAbsoluteZoom(rend->scrollTop(), rend);
     return 0;
 }

 void Element::setScrollLeft(int newLeft)
 {
     document()->updateLayoutIgnorePendingStylesheets();
     if (RenderBox* rend = renderBox())
         rend->setScrollLeft(static_cast<int>(newLeft * rend->style()->effectiveZoom()));
 }

 void Element::setScrollTop(int newTop)
 {
     document()->updateLayoutIgnorePendingStylesheets();
     if (RenderBox* rend = renderBox())
         rend->setScrollTop(static_cast<int>(newTop * rend->style()->effectiveZoom()));
 }

 int Element::scrollWidth()
 {
     document()->updateLayoutIgnorePendingStylesheets();
     if (RenderBox* rend = renderBox())
         return adjustForAbsoluteZoom(rend->scrollWidth(), rend);
     return 0;
 }

 int Element::scrollHeight()
 {
     document()->updateLayoutIgnorePendingStylesheets();
     if (RenderBox* rend = renderBox())
         return adjustForAbsoluteZoom(rend->scrollHeight(), rend);
     return 0;
 }

 IntRect Element::boundsInRootViewSpace()
 {
     document()->updateLayoutIgnorePendingStylesheets();

     FrameView* view = document()->view();
     if (!view)
         return IntRect();

     Vector<FloatQuad> quads;
 #if ENABLE(SVG)
     if (isSVGElement() && renderer()) {
         // Get the bounding rectangle from the SVG model.
         SVGElement* svgElement = static_cast<SVGElement*>(this);
         FloatRect localRect;
         if (svgElement->getBoundingBox(localRect))
             quads.append(renderer()->localToAbsoluteQuad(localRect));
     } else
 #endif
     {
         // Get the bounding rectangle from the box model.
         if (renderBoxModelObject())
             renderBoxModelObject()->absoluteQuads(quads);
     }

     if (quads.isEmpty())
         return IntRect();

     IntRect result = quads[0].enclosingBoundingBox();
     for (size_t i = 1; i < quads.size(); ++i)
         result.unite(quads[i].enclosingBoundingBox());

     result = view->contentsToRootView(result);
     return result;
 }

 PassRefPtr<ClientRectList> Element::getClientRects()
 {
     document()->updateLayoutIgnorePendingStylesheets();

     RenderBoxModelObject* renderBoxModelObject = this->renderBoxModelObject();
     if (!renderBoxModelObject)
         return ClientRectList::create();

     // FIXME: Handle SVG elements.
     // FIXME: Handle table/inline-table with a caption.

     Vector<FloatQuad> quads;
     renderBoxModelObject->absoluteQuads(quads);
     document()->adjustFloatQuadsForScrollAndAbsoluteZoomAndFrameScale(quads, renderBoxModelObject);
     return ClientRectList::create(quads);
 }

 PassRefPtr<ClientRect> Element::getBoundingClientRect()
 {
     document()->updateLayoutIgnorePendingStylesheets();

     Vector<FloatQuad> quads;
 #if ENABLE(SVG)
     if (isSVGElement() && renderer() && !renderer()->isSVGRoot()) {
         // Get the bounding rectangle from the SVG model.
         SVGElement* svgElement = static_cast<SVGElement*>(this);
         FloatRect localRect;
         if (svgElement->getBoundingBox(localRect))
             quads.append(renderer()->localToAbsoluteQuad(localRect));
     } else
 #endif
     {
         // Get the bounding rectangle from the box model.
         if (renderBoxModelObject())
             renderBoxModelObject()->absoluteQuads(quads);
     }

     if (quads.isEmpty())
         return ClientRect::create();

     FloatRect result = quads[0].boundingBox();
     for (size_t i = 1; i < quads.size(); ++i)
         result.unite(quads[i].boundingBox());

     document()->adjustFloatRectForScrollAndAbsoluteZoomAndFrameScale(result, renderer());
     return ClientRect::create(result);
 }

 IntRect Element::screenRect() const
 {
     if (!renderer())
         return IntRect();
     // FIXME: this should probably respect transforms
     return renderer()->view()->frameView()->contentsToScreen(renderer()->absoluteBoundingBoxRectIgnoringTransforms());
 }

 static inline bool shouldIgnoreAttributeCase(const Element* e)
 {
     return e && e->document()->isHTMLDocument() && e->isHTMLElement();
 }

 const AtomicString& Element::getAttribute(const AtomicString& name) const
 {
     bool ignoreCase = shouldIgnoreAttributeCase(this);

     // Update the 'style' attribute if it's invalid and being requested:
     if (!isStyleAttributeValid() && equalPossiblyIgnoringCase(name, styleAttr.localName(), ignoreCase))
         updateStyleAttribute();

 #if ENABLE(SVG)
     if (!areSVGAttributesValid()) {
         // We're not passing a namespace argument on purpose. SVGNames::*Attr are defined w/o namespaces as well.
         updateAnimatedSVGAttribute(QualifiedName(nullAtom, name, nullAtom));
     }
 #endif

     if (attributeData()) {
         if (const Attribute* attribute = attributeData()->getAttributeItem(name, ignoreCase))
             return attribute->value();
     }

     return nullAtom;
 }

 const AtomicString& Element::getAttributeNS(const AtomicString& namespaceURI, const AtomicString& localName) const
 {
     return getAttribute(QualifiedName(nullAtom, localName, namespaceURI));
 }

 void Element::setAttribute(const AtomicString& name, const AtomicString& value, ExceptionCode& ec)
 {
     if (!Document::isValidName(name)) {
         ec = INVALID_CHARACTER_ERR;
         return;
     }

     const AtomicString& localName = shouldIgnoreAttributeCase(this) ? name.lower() : name;

     size_t index = ensureUpdatedAttributeData()->getAttributeItemIndex(localName, false);
     const QualifiedName& qName = index != notFound ? attributeItem(index)->name() : QualifiedName(nullAtom, localName, nullAtom);
     setAttributeInternal(index, qName, value, NotInSynchronizationOfLazyAttribute);
 }

 void Element::setAttribute(const QualifiedName& name, const AtomicString& value)
 {
     setAttributeInternal(ensureUpdatedAttributeData()->getAttributeItemIndex(name), name, value, NotInSynchronizationOfLazyAttribute);
 }

 void Element::setSynchronizedLazyAttribute(const QualifiedName& name, const AtomicString& value)
 {
     setAttributeInternal(mutableAttributeData()->getAttributeItemIndex(name), name, value, InSynchronizationOfLazyAttribute);
 }

 inline void Element::setAttributeInternal(size_t index, const QualifiedName& name, const AtomicString& newValue, SynchronizationOfLazyAttribute inSynchronizationOfLazyAttribute)
 {
     ElementAttributeData* attributeData = mutableAttributeData();

     Attribute* existingAttribute = index != notFound ? attributeData->attributeItem(index) : 0;
     if (newValue.isNull()) {
         if (existingAttribute)
             removeAttributeInternal(index, inSynchronizationOfLazyAttribute);
         return;
     }

     if (!existingAttribute) {
         addAttributeInternal(name, newValue, inSynchronizationOfLazyAttribute);
         return;
     }

     if (!inSynchronizationOfLazyAttribute)
         willModifyAttribute(name, existingAttribute->value(), newValue);

     // If there is an Attr node hooked to this attribute, the Attr::setValue() call below
     // will write into the ElementAttributeData.
     // FIXME: Refactor this so it makes some sense.
     if (RefPtr<Attr> attrNode = attrIfExists(name))
         attrNode->setValue(newValue);
     else
         existingAttribute->setValue(newValue);

     if (!inSynchronizationOfLazyAttribute)
         didModifyAttribute(name, newValue);
 }

 static inline AtomicString makeIdForStyleResolution(const AtomicString& value, bool inQuirksMode)
 {
     if (inQuirksMode)
         return value.lower();
     return value;
 }

 static bool checkNeedsStyleInvalidationForIdChange(const AtomicString& oldId, const AtomicString& newId, StyleResolver* styleResolver)
 {
     ASSERT(newId != oldId);
     if (!oldId.isEmpty() && styleResolver->hasSelectorForId(oldId))
         return true;
     if (!newId.isEmpty() && styleResolver->hasSelectorForId(newId))
         return true;
     return false;
 }

 void Element::attributeChanged(const QualifiedName& name, const AtomicString& newValue)
 {
     parseAttribute(Attribute(name, newValue));

     document()->incDOMTreeVersion();

     StyleResolver* styleResolver = document()->styleResolverIfExists();
     bool testShouldInvalidateStyle = attached() && styleResolver && styleChangeType() < FullStyleChange;
     bool shouldInvalidateStyle = false;

     if (isIdAttributeName(name)) {
         AtomicString oldId = attributeData()->idForStyleResolution();
         AtomicString newId = makeIdForStyleResolution(newValue, document()->inQuirksMode());
         if (newId != oldId) {
             attributeData()->setIdForStyleResolution(newId);
             shouldInvalidateStyle = testShouldInvalidateStyle && checkNeedsStyleInvalidationForIdChange(oldId, newId, styleResolver);
         }
     } else if (name == HTMLNames::nameAttr)
         setHasName(!newValue.isNull());

     shouldInvalidateStyle |= testShouldInvalidateStyle && styleResolver->hasSelectorForAttribute(name.localName());

     invalidateNodeListCachesInAncestors(&name, this);

     if (shouldInvalidateStyle)
         setNeedsStyleRecalc();

     if (AXObjectCache::accessibilityEnabled())
         document()->axObjectCache()->handleAttributeChanged(name, this);
 }

 void Element::parseAttribute(const Attribute& attribute)
 {
     if (attribute.name() == classAttr)
         classAttributeChanged(attribute.value());
 }

 template <typename CharacterType>
 static inline bool classStringHasClassName(const CharacterType* characters, unsigned length)
 {
     ASSERT(length > 0);

     unsigned i = 0;
     do {
         if (isNotHTMLSpace(characters[i]))
             break;
         ++i;
     } while (i < length);

     return i < length;
 }

 static inline bool classStringHasClassName(const AtomicString& newClassString)
 {
     unsigned length = newClassString.length();

     if (!length)
         return false;

     if (newClassString.is8Bit())
         return classStringHasClassName(newClassString.characters8(), length);
     return classStringHasClassName(newClassString.characters16(), length);
 }

 static bool checkNeedsStyleInvalidationForClassChange(const SpaceSplitString& changedClasses, StyleResolver* styleResolver)
 {
     unsigned changedSize = changedClasses.size();
     for (unsigned i = 0; i < changedSize; ++i) {
         if (styleResolver->hasSelectorForClass(changedClasses[i]))
             return true;
     }
     return false;
 }

 static bool checkNeedsStyleInvalidationForClassChange(const SpaceSplitString& oldClasses, const SpaceSplitString& newClasses, StyleResolver* styleResolver)
 {
     unsigned oldSize = oldClasses.size();
     if (!oldSize)
         return checkNeedsStyleInvalidationForClassChange(newClasses, styleResolver);
     BitVector remainingClassBits;
     remainingClassBits.ensureSize(oldSize);
     // Class vectors tend to be very short. This is faster than using a hash table.
     unsigned newSize = newClasses.size();
     for (unsigned i = 0; i < newSize; ++i) {
         for (unsigned j = 0; j < oldSize; ++j) {
             if (newClasses[i] == oldClasses[j]) {
                 remainingClassBits.quickSet(j);
                 continue;
             }
         }
         if (styleResolver->hasSelectorForClass(newClasses[i]))
             return true;
     }
     for (unsigned i = 0; i < oldSize; ++i) {
         // If the bit is not set the the corresponding class has been removed.
         if (remainingClassBits.quickGet(i))
             continue;
         if (styleResolver->hasSelectorForClass(oldClasses[i]))
             return true;
     }
     return false;
 }

 void Element::classAttributeChanged(const AtomicString& newClassString)
 {
     StyleResolver* styleResolver = document()->styleResolverIfExists();
     bool testShouldInvalidateStyle = attached() && styleResolver && styleChangeType() < FullStyleChange;
     bool shouldInvalidateStyle = false;

     if (classStringHasClassName(newClassString)) {
         const ElementAttributeData* attributeData = ensureAttributeData();
         const bool shouldFoldCase = document()->inQuirksMode();
         const SpaceSplitString oldClasses = attributeData->classNames();

         attributeData->setClass(newClassString, shouldFoldCase);

         const SpaceSplitString& newClasses = attributeData->classNames();
         shouldInvalidateStyle = testShouldInvalidateStyle && checkNeedsStyleInvalidationForClassChange(oldClasses, newClasses, styleResolver);
     } else if (const ElementAttributeData* attributeData = this->attributeData()) {
         const SpaceSplitString& oldClasses = attributeData->classNames();
         shouldInvalidateStyle = testShouldInvalidateStyle && checkNeedsStyleInvalidationForClassChange(oldClasses, styleResolver);

         attributeData->clearClass();
     }

     if (DOMTokenList* classList = optionalClassList())
         static_cast<ClassList*>(classList)->reset(newClassString);

     if (shouldInvalidateStyle)
         setNeedsStyleRecalc();
 }

 // Returns true is the given attribute is an event handler.
 // We consider an event handler any attribute that begins with "on".
 // It is a simple solution that has the advantage of not requiring any
 // code or configuration change if a new event handler is defined.

 static bool isEventHandlerAttribute(const QualifiedName& name)
 {
     return name.namespaceURI().isNull() && name.localName().startsWith("on");
 }

 // FIXME: Share code with Element::isURLAttribute.
 static bool isAttributeToRemove(const QualifiedName& name, const AtomicString& value)
 {
     return (name.localName() == hrefAttr.localName() || name.localName() == nohrefAttr.localName()
         || name == srcAttr || name == actionAttr || name == formactionAttr) && protocolIsJavaScript(stripLeadingAndTrailingHTMLSpaces(value));
 }

 void Element::parserSetAttributes(const Vector<Attribute>& attributeVector, FragmentScriptingPermission scriptingPermission)
 {
     ASSERT(!inDocument());
     ASSERT(!parentNode());

     ASSERT(!m_attributeData);

     if (attributeVector.isEmpty())
         return;

     Vector<Attribute> filteredAttributes = attributeVector;

     // If the element is created as result of a paste or drag-n-drop operation
     // we want to remove all the script and event handlers.
     if (scriptingPermission == DisallowScriptingContent) {
         unsigned i = 0;
         while (i < filteredAttributes.size()) {
             Attribute& attribute = filteredAttributes[i];
             if (isEventHandlerAttribute(attribute.name())) {
                 filteredAttributes.remove(i);
                 continue;
             }

             if (isAttributeToRemove(attribute.name(), attribute.value()))
                 attribute.setValue(emptyAtom);
             i++;
         }
     }

     // When the document is in parsing state, we cache immutable ElementAttributeData objects with the
     // input attribute vector (and the tag name) as key. (This cache is held by Document.)
     if (!document() || !document()->parsing())
         m_attributeData = ElementAttributeData::createImmutable(filteredAttributes);
     else
         m_attributeData = document()->cachedImmutableAttributeData(this, filteredAttributes);

     // Iterate over the set of attributes we already have on the stack in case
     // attributeChanged mutates m_attributeData.
     // FIXME: Find a way so we don't have to do this.
     for (unsigned i = 0; i < filteredAttributes.size(); ++i)
         attributeChanged(filteredAttributes[i].name(), filteredAttributes[i].value());
 }

 bool Element::hasAttributes() const
 {
     updateInvalidAttributes();
     return attributeData() && attributeData()->length();
 }

 bool Element::hasEquivalentAttributes(const Element* other) const
 {
     const ElementAttributeData* attributeData = updatedAttributeData();
     const ElementAttributeData* otherAttributeData = other->updatedAttributeData();
     if (attributeData)
         return attributeData->isEquivalent(otherAttributeData);
     if (otherAttributeData)
         return otherAttributeData->isEquivalent(attributeData);
     return true;
 }

 String Element::nodeName() const
 {
     return m_tagName.toString();
 }

 String Element::nodeNamePreservingCase() const
 {
     return m_tagName.toString();
 }

 void Element::setPrefix(const AtomicString& prefix, ExceptionCode& ec)
 {
     ec = 0;
     checkSetPrefix(prefix, ec);
     if (ec)
         return;

     m_tagName.setPrefix(prefix.isEmpty() ? AtomicString() : prefix);
 }

 KURL Element::baseURI() const
 {
     const AtomicString& baseAttribute = getAttribute(baseAttr);
     KURL base(KURL(), baseAttribute);
     if (!base.protocol().isEmpty())
         return base;

     ContainerNode* parent = parentNode();
     if (!parent)
         return base;

     const KURL& parentBase = parent->baseURI();
     if (parentBase.isNull())
         return base;

     return KURL(parentBase, baseAttribute);
 }

 const QualifiedName& Element::imageSourceAttributeName() const
 {
     return srcAttr;
 }

 RenderObject* Element::createRenderer(RenderArena* arena, RenderStyle* style)
 {
     if (document()->documentElement() == this && style->display() == NONE) {
         // Ignore display: none on root elements.  Force a display of block in that case.
         RenderBlock* result = new (arena) RenderBlock(this);
         if (result)
             result->setAnimatableStyle(style);
         return result;
     }
     return RenderObject::createObject(this, style);
 }

 bool Element::wasChangedSinceLastFormControlChangeEvent() const
 {
     return false;
 }

 void Element::setChangedSinceLastFormControlChangeEvent(bool)
 {
 }

 Node::InsertionNotificationRequest Element::insertedInto(ContainerNode* insertionPoint)
 {
     // need to do superclass processing first so inDocument() is true
     // by the time we reach updateId
     ContainerNode::insertedInto(insertionPoint);

 #if ENABLE(FULLSCREEN_API)
     if (containsFullScreenElement() && parentElement() && !parentElement()->containsFullScreenElement())
         setContainsFullScreenElementOnAncestorsCrossingFrameBoundaries(true);
 #endif

     if (!insertionPoint->inDocument())
         return InsertionDone;

     const AtomicString& idValue = getIdAttribute();
     if (!idValue.isNull())
         updateId(nullAtom, idValue);

     const AtomicString& nameValue = getNameAttribute();
     if (!nameValue.isNull())
         updateName(nullAtom, nameValue);

     if (hasTagName(labelTag)) {
         TreeScope* scope = treeScope();
         if (scope->shouldCacheLabelsByForAttribute())
             updateLabel(scope, nullAtom, fastGetAttribute(forAttr));
     }

     return InsertionDone;
 }

 void Element::removedFrom(ContainerNode* insertionPoint)
 {
 #if ENABLE(FULLSCREEN_API)
     if (containsFullScreenElement())
         setContainsFullScreenElementOnAncestorsCrossingFrameBoundaries(false);
 #endif
 #if ENABLE(POINTER_LOCK)
     if (document()->page())
         document()->page()->pointerLockController()->elementRemoved(this);
 #endif

     setSavedLayerScrollOffset(IntSize());

     if (insertionPoint->inDocument()) {
         const AtomicString& idValue = getIdAttribute();
         if (!idValue.isNull() && inDocument())
             updateId(insertionPoint->treeScope(), idValue, nullAtom);

         const AtomicString& nameValue = getNameAttribute();
         if (!nameValue.isNull())
             updateName(nameValue, nullAtom);

         if (hasTagName(labelTag)) {
             TreeScope* treeScope = insertionPoint->treeScope();
             if (treeScope->shouldCacheLabelsByForAttribute())
                 updateLabel(treeScope, fastGetAttribute(forAttr), nullAtom);
         }
     }

     ContainerNode::removedFrom(insertionPoint);
 }

 void Element::attach()
 {
     suspendPostAttachCallbacks();
     WidgetHierarchyUpdatesSuspensionScope suspendWidgetHierarchyUpdates;

     createRendererIfNeeded();
     StyleResolverParentPusher parentPusher(this);

     if (parentElement() && parentElement()->isInCanvasSubtree())
         setIsInCanvasSubtree(true);

     // When a shadow root exists, it does the work of attaching the children.
     if (ElementShadow* shadow = this->shadow()) {
         parentPusher.push();
         shadow->attach();
     } else {
         if (firstChild())
             parentPusher.push();
     }
     ContainerNode::attach();

     if (hasRareData()) {
         ElementRareData* data = elementRareData();
         if (data->needsFocusAppearanceUpdateSoonAfterAttach()) {
             if (isFocusable() && document()->focusedNode() == this)
                 document()->updateFocusAppearanceSoon(false /* don't restore selection */);
             data->setNeedsFocusAppearanceUpdateSoonAfterAttach(false);
         }
     }

     resumePostAttachCallbacks();
 }

 void Element::unregisterNamedFlowContentNode()
 {
     if (document()->cssRegionsEnabled() && inNamedFlow()) {
         if (document()->renderer() && document()->renderer()->view())
             document()->renderer()->view()->flowThreadController()->unregisterNamedFlowContentNode(this);
     }
 }

 void Element::detach()
 {
     WidgetHierarchyUpdatesSuspensionScope suspendWidgetHierarchyUpdates;
     unregisterNamedFlowContentNode();
     cancelFocusAppearanceUpdate();
     if (hasRareData()) {
         ElementRareData* data = elementRareData();
         data->setIsInCanvasSubtree(false);
         data->resetComputedStyle();
     }

     if (ElementShadow* shadow = this->shadow()) {
         detachChildrenIfNeeded();
         shadow->detach();
     }
     ContainerNode::detach();
 }

 bool Element::pseudoStyleCacheIsInvalid(const RenderStyle* currentStyle, RenderStyle* newStyle)
 {
     ASSERT(currentStyle == renderStyle());
     ASSERT(renderer());

     if (!currentStyle)
         return false;

     const PseudoStyleCache* pseudoStyleCache = currentStyle->cachedPseudoStyles();
     if (!pseudoStyleCache)
         return false;

     size_t cacheSize = pseudoStyleCache->size();
     for (size_t i = 0; i < cacheSize; ++i) {
         RefPtr<RenderStyle> newPseudoStyle;
         PseudoId pseudoId = pseudoStyleCache->at(i)->styleType();
         if (pseudoId == FIRST_LINE || pseudoId == FIRST_LINE_INHERITED)
             newPseudoStyle = renderer()->uncachedFirstLineStyle(newStyle);
         else
             newPseudoStyle = renderer()->getUncachedPseudoStyle(pseudoId, newStyle, newStyle);
         if (!newPseudoStyle)
             return true;
         if (*newPseudoStyle != *pseudoStyleCache->at(i)) {
             if (pseudoId < FIRST_INTERNAL_PSEUDOID)
                 newStyle->setHasPseudoStyle(pseudoId);
             newStyle->addCachedPseudoStyle(newPseudoStyle);
             if (pseudoId == FIRST_LINE || pseudoId == FIRST_LINE_INHERITED) {
                 // FIXME: We should do an actual diff to determine whether a repaint vs. layout
                 // is needed, but for now just assume a layout will be required.  The diff code
                 // in RenderObject::setStyle would need to be factored out so that it could be reused.
                 renderer()->setNeedsLayoutAndPrefWidthsRecalc();
             }
             return true;
         }
     }
     return false;
 }

 PassRefPtr<RenderStyle> Element::styleForRenderer()
 {
     if (hasCustomCallbacks()) {
         if (RefPtr<RenderStyle> style = customStyleForRenderer())
             return style.release();
     }

     return document()->styleResolver()->styleForElement(this);
 }

 void Element::recalcStyle(StyleChange change)
 {
     if (hasCustomCallbacks()) {
         if (!willRecalcStyle(change))
             return;
     }

     // Ref currentStyle in case it would otherwise be deleted when setting the new style in the renderer.
     RefPtr<RenderStyle> currentStyle(renderStyle());
     bool hasParentStyle = parentNodeForRenderingAndStyle() ? static_cast<bool>(parentNodeForRenderingAndStyle()->renderStyle()) : false;
     bool hasDirectAdjacentRules = currentStyle && currentStyle->childrenAffectedByDirectAdjacentRules();
     bool hasIndirectAdjacentRules = currentStyle && currentStyle->childrenAffectedByForwardPositionalRules();

     if ((change > NoChange || needsStyleRecalc())) {
         if (hasRareData()) {
             ElementRareData* data = elementRareData();
             data->resetComputedStyle();
             data->setStyleAffectedByEmpty(false);
         }
     }
     if (hasParentStyle && (change >= Inherit || needsStyleRecalc())) {
         RefPtr<RenderStyle> newStyle = styleForRenderer();
         StyleChange ch = Node::diff(currentStyle.get(), newStyle.get(), document());
         if (ch == Detach || !currentStyle) {
             // FIXME: The style gets computed twice by calling attach. We could do better if we passed the style along.
             reattach();
             // attach recalculates the style for all children. No need to do it twice.
             clearNeedsStyleRecalc();
             clearChildNeedsStyleRecalc();

             if (hasCustomCallbacks())
                 didRecalcStyle(change);
             return;
         }

         if (currentStyle) {
             // Preserve "affected by" bits that were propagated to us from descendants in the case where we didn't do a full
             // style change (e.g., only inline style changed).
             if (currentStyle->affectedByHoverRules())
                 newStyle->setAffectedByHoverRules(true);
             if (currentStyle->affectedByActiveRules())
                 newStyle->setAffectedByActiveRules(true);
             if (currentStyle->affectedByDragRules())
                 newStyle->setAffectedByDragRules(true);
             if (currentStyle->childrenAffectedByForwardPositionalRules())
                 newStyle->setChildrenAffectedByForwardPositionalRules();
             if (currentStyle->childrenAffectedByBackwardPositionalRules())
                 newStyle->setChildrenAffectedByBackwardPositionalRules();
             if (currentStyle->childrenAffectedByFirstChildRules())
                 newStyle->setChildrenAffectedByFirstChildRules();
             if (currentStyle->childrenAffectedByLastChildRules())
                 newStyle->setChildrenAffectedByLastChildRules();
             if (currentStyle->childrenAffectedByDirectAdjacentRules())
                 newStyle->setChildrenAffectedByDirectAdjacentRules();
         }

         if (RenderObject* renderer = this->renderer()) {
             if (ch != NoChange || pseudoStyleCacheIsInvalid(currentStyle.get(), newStyle.get()) || (change == Force && renderer->requiresForcedStyleRecalcPropagation()) || styleChangeType() == SyntheticStyleChange)
                 renderer->setAnimatableStyle(newStyle.get());
             else if (needsStyleRecalc()) {
                 // Although no change occurred, we use the new style so that the cousin style sharing code won't get
                 // fooled into believing this style is the same.
                 renderer->setStyleInternal(newStyle.get());
             }
         }

         // If "rem" units are used anywhere in the document, and if the document element's font size changes, then go ahead and force font updating
         // all the way down the tree. This is simpler than having to maintain a cache of objects (and such font size changes should be rare anyway).
         if (document()->styleSheetCollection()->usesRemUnits() && document()->documentElement() == this && ch != NoChange && currentStyle && newStyle && currentStyle->fontSize() != newStyle->fontSize()) {
             // Cached RenderStyles may depend on the rem units.
             document()->styleResolver()->invalidateMatchedPropertiesCache();
             change = Force;
         }

         if (change != Force) {
             if (styleChangeType() >= FullStyleChange)
                 change = Force;
             else
                 change = ch;
         }
     }
     StyleResolverParentPusher parentPusher(this);

     // FIXME: This does not care about sibling combinators. Will be necessary in XBL2 world.
     if (ElementShadow* shadow = this->shadow()) {
         if (change >= Inherit || shadow->childNeedsStyleRecalc() || shadow->needsStyleRecalc()) {
             parentPusher.push();
             shadow->recalcStyle(change);
         }
     }

     // FIXME: This check is good enough for :hover + foo, but it is not good enough for :hover + foo + bar.
     // For now we will just worry about the common case, since it's a lot trickier to get the second case right
     // without doing way too much re-resolution.
     bool forceCheckOfNextElementSibling = false;
     bool forceCheckOfAnyElementSibling = false;
     for (Node *n = firstChild(); n; n = n->nextSibling()) {
         if (n->isTextNode()) {
             toText(n)->recalcTextStyle(change);
             continue;
         }
         if (!n->isElementNode())
             continue;
         Element* element = static_cast<Element*>(n);
         bool childRulesChanged = element->needsStyleRecalc() && element->styleChangeType() == FullStyleChange;
         if ((forceCheckOfNextElementSibling || forceCheckOfAnyElementSibling))
             element->setNeedsStyleRecalc();
         if (change >= Inherit || element->childNeedsStyleRecalc() || element->needsStyleRecalc()) {
             parentPusher.push();
             element->recalcStyle(change);
         }
         forceCheckOfNextElementSibling = childRulesChanged && hasDirectAdjacentRules;
         forceCheckOfAnyElementSibling = forceCheckOfAnyElementSibling || (childRulesChanged && hasIndirectAdjacentRules);
     }

     clearNeedsStyleRecalc();
     clearChildNeedsStyleRecalc();

     if (hasCustomCallbacks())
         didRecalcStyle(change);
 }

 ElementShadow* Element::shadow() const
 {
     if (!hasRareData())
         return 0;

     return elementRareData()->m_shadow.get();
 }

 ElementShadow* Element::ensureShadow()
 {
     if (ElementShadow* shadow = ensureElementRareData()->m_shadow.get())
         return shadow;

     ElementRareData* data = elementRareData();
     data->m_shadow = adoptPtr(new ElementShadow());
     return data->m_shadow.get();
 }

 ShadowRoot* Element::userAgentShadowRoot() const
 {
     if (ElementShadow* elementShadow = shadow()) {
         if (ShadowRoot* shadowRoot = elementShadow->oldestShadowRoot()) {
             ASSERT(shadowRoot->type() == ShadowRoot::UserAgentShadowRoot);
             return shadowRoot;
         }
     }

     return 0;
 }

 const AtomicString& Element::shadowPseudoId() const
 {
     return hasRareData() ? elementRareData()->m_shadowPseudoId : nullAtom;
 }

 void Element::setShadowPseudoId(const AtomicString& id, ExceptionCode& ec)
 {
     if (!hasRareData() && id == nullAtom)
         return;

     if (!CSSSelector::isUnknownPseudoType(id)) {
         ec = SYNTAX_ERR;
         return;
     }

     ensureElementRareData()->m_shadowPseudoId = id;
 }

 bool Element::childTypeAllowed(NodeType type) const
 {
     switch (type) {
     case ELEMENT_NODE:
     case TEXT_NODE:
     case COMMENT_NODE:
     case PROCESSING_INSTRUCTION_NODE:
     case CDATA_SECTION_NODE:
     case ENTITY_REFERENCE_NODE:
         return true;
     default:
         break;
     }
     return false;
 }

 static void checkForEmptyStyleChange(Element* element, RenderStyle* style)
 {
     if (!style && !element->styleAffectedByEmpty())
         return;

     if (!style || (style->affectedByEmpty() && (!style->emptyState() || element->hasChildNodes())))
         element->setNeedsStyleRecalc();
 }

 static void checkForSiblingStyleChanges(Element* e, RenderStyle* style, bool finishedParsingCallback,
                                         Node* beforeChange, Node* afterChange, int childCountDelta)
 {
     // :empty selector.
     checkForEmptyStyleChange(e, style);

     if (!style || (e->needsStyleRecalc() && style->childrenAffectedByPositionalRules()))
         return;

     // :first-child.  In the parser callback case, we don't have to check anything, since we were right the first time.
     // In the DOM case, we only need to do something if |afterChange| is not 0.
     // |afterChange| is 0 in the parser case, so it works out that we'll skip this block.
     if (style->childrenAffectedByFirstChildRules() && afterChange) {
         // Find our new first child.
         Node* newFirstChild = 0;
         for (newFirstChild = e->firstChild(); newFirstChild && !newFirstChild->isElementNode(); newFirstChild = newFirstChild->nextSibling()) {};

         // Find the first element node following |afterChange|
         Node* firstElementAfterInsertion = 0;
         for (firstElementAfterInsertion = afterChange;
              firstElementAfterInsertion && !firstElementAfterInsertion->isElementNode();
              firstElementAfterInsertion = firstElementAfterInsertion->nextSibling()) {};

         // This is the insert/append case.
         if (newFirstChild != firstElementAfterInsertion && firstElementAfterInsertion && firstElementAfterInsertion->attached() &&
             firstElementAfterInsertion->renderStyle() && firstElementAfterInsertion->renderStyle()->firstChildState())
             firstElementAfterInsertion->setNeedsStyleRecalc();

         // We also have to handle node removal.
         if (childCountDelta < 0 && newFirstChild == firstElementAfterInsertion && newFirstChild && (!newFirstChild->renderStyle() || !newFirstChild->renderStyle()->firstChildState()))
             newFirstChild->setNeedsStyleRecalc();
     }

     // :last-child.  In the parser callback case, we don't have to check anything, since we were right the first time.
     // In the DOM case, we only need to do something if |afterChange| is not 0.
     if (style->childrenAffectedByLastChildRules() && beforeChange) {
         // Find our new last child.
         Node* newLastChild = 0;
         for (newLastChild = e->lastChild(); newLastChild && !newLastChild->isElementNode(); newLastChild = newLastChild->previousSibling()) {};

         // Find the last element node going backwards from |beforeChange|
         Node* lastElementBeforeInsertion = 0;
         for (lastElementBeforeInsertion = beforeChange;
              lastElementBeforeInsertion && !lastElementBeforeInsertion->isElementNode();
              lastElementBeforeInsertion = lastElementBeforeInsertion->previousSibling()) {};

         if (newLastChild != lastElementBeforeInsertion && lastElementBeforeInsertion && lastElementBeforeInsertion->attached() &&
             lastElementBeforeInsertion->renderStyle() && lastElementBeforeInsertion->renderStyle()->lastChildState())
             lastElementBeforeInsertion->setNeedsStyleRecalc();

         // We also have to handle node removal.  The parser callback case is similar to node removal as well in that we need to change the last child
         // to match now.
         if ((childCountDelta < 0 || finishedParsingCallback) && newLastChild == lastElementBeforeInsertion && newLastChild && (!newLastChild->renderStyle() || !newLastChild->renderStyle()->lastChildState()))
             newLastChild->setNeedsStyleRecalc();
     }

     // The + selector.  We need to invalidate the first element following the insertion point.  It is the only possible element
     // that could be affected by this DOM change.
     if (style->childrenAffectedByDirectAdjacentRules() && afterChange) {
         Node* firstElementAfterInsertion = 0;
         for (firstElementAfterInsertion = afterChange;
              firstElementAfterInsertion && !firstElementAfterInsertion->isElementNode();
              firstElementAfterInsertion = firstElementAfterInsertion->nextSibling()) {};
         if (firstElementAfterInsertion && firstElementAfterInsertion->attached())
             firstElementAfterInsertion->setNeedsStyleRecalc();
     }

     // Forward positional selectors include the ~ selector, nth-child, nth-of-type, first-of-type and only-of-type.
     // Backward positional selectors include nth-last-child, nth-last-of-type, last-of-type and only-of-type.
     // We have to invalidate everything following the insertion point in the forward case, and everything before the insertion point in the
     // backward case.
     // |afterChange| is 0 in the parser callback case, so we won't do any work for the forward case if we don't have to.
     // For performance reasons we just mark the parent node as changed, since we don't want to make childrenChanged O(n^2) by crawling all our kids
     // here.  recalcStyle will then force a walk of the children when it sees that this has happened.
     if ((style->childrenAffectedByForwardPositionalRules() && afterChange) ||
         (style->childrenAffectedByBackwardPositionalRules() && beforeChange))
         e->setNeedsStyleRecalc();
 }

 void Element::childrenChanged(bool changedByParser, Node* beforeChange, Node* afterChange, int childCountDelta)
 {
     ContainerNode::childrenChanged(changedByParser, beforeChange, afterChange, childCountDelta);
     if (changedByParser)
         checkForEmptyStyleChange(this, renderStyle());
     else
         checkForSiblingStyleChanges(this, renderStyle(), false, beforeChange, afterChange, childCountDelta);

     if (ElementShadow * shadow = this->shadow())
         shadow->invalidateDistribution();
 }

 void Element::beginParsingChildren()
 {
     clearIsParsingChildrenFinished();
     StyleResolver* styleResolver = document()->styleResolverIfExists();
     if (styleResolver && attached())
         styleResolver->pushParentElement(this);
 }

 void Element::finishParsingChildren()
 {
     ContainerNode::finishParsingChildren();
     setIsParsingChildrenFinished();
     checkForSiblingStyleChanges(this, renderStyle(), true, lastChild(), 0, 0);
     if (StyleResolver* styleResolver = document()->styleResolverIfExists())
         styleResolver->popParentElement(this);
 }

 #ifndef NDEBUG
 void Element::formatForDebugger(char* buffer, unsigned length) const
 {
     StringBuilder result;
     String s;

     result.append(nodeName());

     s = getIdAttribute();
     if (s.length() > 0) {
         if (result.length() > 0)
             result.appendLiteral("; ");
         result.appendLiteral("id=");
         result.append(s);
     }

     s = getAttribute(classAttr);
     if (s.length() > 0) {
         if (result.length() > 0)
             result.appendLiteral("; ");
         result.appendLiteral("class=");
         result.append(s);
     }

     strncpy(buffer, result.toString().utf8().data(), length - 1);
 }
 #endif

 PassRefPtr<Attr> Element::setAttributeNode(Attr* attr, ExceptionCode& ec)
 {
     if (!attr) {
         ec = TYPE_MISMATCH_ERR;
         return 0;
     }

     RefPtr<Attr> oldAttr = attrIfExists(attr->qualifiedName());
     if (oldAttr.get() == attr)
         return attr; // This Attr is already attached to the element.

     // INUSE_ATTRIBUTE_ERR: Raised if node is an Attr that is already an attribute of another Element object.
     // The DOM user must explicitly clone Attr nodes to re-use them in other elements.
     if (attr->ownerElement()) {
         ec = INUSE_ATTRIBUTE_ERR;
         return 0;
     }

     updateInvalidAttributes();
     ElementAttributeData* attributeData = mutableAttributeData();

     size_t index = attributeData->getAttributeItemIndex(attr->qualifiedName());
     if (index != notFound) {
         if (oldAttr)
             oldAttr->detachFromElementWithValue(attributeData->attributeItem(index)->value());
         else
             oldAttr = Attr::create(document(), attr->qualifiedName(), attributeData->attributeItem(index)->value());
     }

     setAttributeInternal(index, attr->qualifiedName(), attr->value(), NotInSynchronizationOfLazyAttribute);
     attributeData->setAttr(this, attr->qualifiedName(), attr);
     return oldAttr.release();
 }

 PassRefPtr<Attr> Element::setAttributeNodeNS(Attr* attr, ExceptionCode& ec)
 {
     return setAttributeNode(attr, ec);
 }

 PassRefPtr<Attr> Element::removeAttributeNode(Attr* attr, ExceptionCode& ec)
 {
     if (!attr) {
         ec = TYPE_MISMATCH_ERR;
         return 0;
     }
     if (attr->ownerElement() != this) {
         ec = NOT_FOUND_ERR;
         return 0;
     }

     ASSERT(document() == attr->document());

     const ElementAttributeData* attributeData = updatedAttributeData();
     ASSERT(attributeData);

     size_t index = attributeData->getAttributeItemIndex(attr->qualifiedName());
     if (index == notFound) {
         ec = NOT_FOUND_ERR;
         return 0;
     }

     return detachAttribute(index);
 }

 bool Element::parseAttributeName(QualifiedName& out, const AtomicString& namespaceURI, const AtomicString& qualifiedName, ExceptionCode& ec)
 {
     String prefix, localName;
     if (!Document::parseQualifiedName(qualifiedName, prefix, localName, ec))
         return false;
     ASSERT(!ec);

     QualifiedName qName(prefix, localName, namespaceURI);

     if (!Document::hasValidNamespaceForAttributes(qName)) {
         ec = NAMESPACE_ERR;
         return false;
     }

     out = qName;
     return true;
 }

 void Element::setAttributeNS(const AtomicString& namespaceURI, const AtomicString& qualifiedName, const AtomicString& value, ExceptionCode& ec)
 {
     QualifiedName parsedName = anyName;
     if (!parseAttributeName(parsedName, namespaceURI, qualifiedName, ec))
         return;
     setAttribute(parsedName, value);
 }

 void Element::removeAttributeInternal(size_t index, SynchronizationOfLazyAttribute inSynchronizationOfLazyAttribute)
 {
     ASSERT(index < attributeCount());

     ElementAttributeData* attributeData = mutableAttributeData();

     QualifiedName name = attributeData->attributeItem(index)->name();
     AtomicString valueBeingRemoved = attributeData->attributeItem(index)->value();

     if (!inSynchronizationOfLazyAttribute) {
         if (!valueBeingRemoved.isNull())
             willModifyAttribute(name, valueBeingRemoved, nullAtom);
     }

     if (hasAttrList()) {
         if (RefPtr<Attr> attr = attributeData->attrIfExists(this, name))
             attr->detachFromElementWithValue(attributeData->attributeItem(index)->value());
     }

     attributeData->removeAttribute(index);

     if (!inSynchronizationOfLazyAttribute)
         didRemoveAttribute(name);
 }

 void Element::addAttributeInternal(const QualifiedName& name, const AtomicString& value, SynchronizationOfLazyAttribute inSynchronizationOfLazyAttribute)
 {
     ASSERT(m_attributeData);
     ASSERT(m_attributeData->isMutable());
     if (!inSynchronizationOfLazyAttribute)
         willModifyAttribute(name, nullAtom, value);
     m_attributeData->addAttribute(Attribute(name, value));
     if (!inSynchronizationOfLazyAttribute)
         didAddAttribute(name, value);
 }

 void Element::removeAttribute(const AtomicString& name)
 {
     if (!attributeData())
         return;

     AtomicString localName = shouldIgnoreAttributeCase(this) ? name.lower() : name;
     size_t index = attributeData()->getAttributeItemIndex(localName, false);
     if (index == notFound)
         return;

     removeAttributeInternal(index, NotInSynchronizationOfLazyAttribute);
 }

 void Element::removeAttributeNS(const AtomicString& namespaceURI, const AtomicString& localName)
 {
     removeAttribute(QualifiedName(nullAtom, localName, namespaceURI));
 }

 PassRefPtr<Attr> Element::getAttributeNode(const AtomicString& name)
 {
     const ElementAttributeData* attributeData = updatedAttributeData();
     if (!attributeData)
         return 0;
     return attributeData->getAttributeNode(name, shouldIgnoreAttributeCase(this), this);
 }

 PassRefPtr<Attr> Element::getAttributeNodeNS(const AtomicString& namespaceURI, const AtomicString& localName)
 {
     const ElementAttributeData* attributeData = updatedAttributeData();
     if (!attributeData)
         return 0;
     return attributeData->getAttributeNode(QualifiedName(nullAtom, localName, namespaceURI), this);
 }

 bool Element::hasAttribute(const AtomicString& name) const
 {
     if (!attributeData())
         return false;

     // This call to String::lower() seems to be required but
     // there may be a way to remove it.
     AtomicString localName = shouldIgnoreAttributeCase(this) ? name.lower() : name;
     return updatedAttributeData()->getAttributeItem(localName, false);
 }

 bool Element::hasAttributeNS(const AtomicString& namespaceURI, const AtomicString& localName) const
 {
     const ElementAttributeData* attributeData = updatedAttributeData();
     if (!attributeData)
         return false;
     return attributeData->getAttributeItem(QualifiedName(nullAtom, localName, namespaceURI));
 }

 CSSStyleDeclaration *Element::style()
 {
     return 0;
 }

 void Element::focus(bool restorePreviousSelection)
 {
     if (!inDocument())
         return;

     Document* doc = document();
     if (doc->focusedNode() == this)
         return;

     // If the stylesheets have already been loaded we can reliably check isFocusable.
     // If not, we continue and set the focused node on the focus controller below so
     // that it can be updated soon after attach.
     if (doc->haveStylesheetsLoaded()) {
         doc->updateLayoutIgnorePendingStylesheets();
         if (!isFocusable())
             return;
     }

     if (!supportsFocus())
         return;

     RefPtr<Node> protect;
     if (Page* page = doc->page()) {
         // Focus and change event handlers can cause us to lose our last ref.
         // If a focus event handler changes the focus to a different node it
         // does not make sense to continue and update appearence.
         protect = this;
         if (!page->focusController()->setFocusedNode(this, doc->frame()))
             return;
     }

     // Setting the focused node above might have invalidated the layout due to scripts.
     doc->updateLayoutIgnorePendingStylesheets();

     if (!isFocusable()) {
         ensureElementRareData()->setNeedsFocusAppearanceUpdateSoonAfterAttach(true);
         return;
     }

     cancelFocusAppearanceUpdate();
     updateFocusAppearance(restorePreviousSelection);
 }

 void Element::updateFocusAppearance(bool /*restorePreviousSelection*/)
 {
     if (isRootEditableElement()) {
         Frame* frame = document()->frame();
         if (!frame)
             return;

         // When focusing an editable element in an iframe, don't reset the selection if it already contains a selection.
         if (this == frame->selection()->rootEditableElement())
             return;

         // FIXME: We should restore the previous selection if there is one.
         VisibleSelection newSelection = VisibleSelection(firstPositionInOrBeforeNode(this), DOWNSTREAM);

         if (frame->selection()->shouldChangeSelection(newSelection)) {
             frame->selection()->setSelection(newSelection);
             frame->selection()->revealSelection();
         }
     } else if (renderer() && !renderer()->isWidget())
         renderer()->scrollRectToVisible(boundingBox());
 }

 void Element::blur()
 {
     cancelFocusAppearanceUpdate();
     Document* doc = document();
     if (treeScope()->focusedNode() == this) {
         if (doc->frame())
             doc->frame()->page()->focusController()->setFocusedNode(0, doc->frame());
         else
             doc->setFocusedNode(0);
     }
 }

 String Element::innerText()
 {
     // We need to update layout, since plainText uses line boxes in the render tree.
     document()->updateLayoutIgnorePendingStylesheets();

     if (!renderer())
         return textContent(true);

     return plainText(rangeOfContents(const_cast<Element*>(this)).get());
 }

 String Element::outerText()
 {
     // Getting outerText is the same as getting innerText, only
     // setting is different. You would think this should get the plain
     // text for the outer range, but this is wrong, <br> for instance
     // would return different values for inner and outer text by such
     // a rule, but it doesn't in WinIE, and we want to match that.
     return innerText();
 }

 String Element::title() const
 {
     return String();
 }

 const AtomicString& Element::pseudo() const
 {
     return getAttribute(pseudoAttr);
 }

 void Element::setPseudo(const AtomicString& value)
 {
     setAttribute(pseudoAttr, value);
 }

 LayoutSize Element::minimumSizeForResizing() const
 {
     return hasRareData() ? elementRareData()->m_minimumSizeForResizing : defaultMinimumSizeForResizing();
 }

 void Element::setMinimumSizeForResizing(const LayoutSize& size)
 {
     if (size == defaultMinimumSizeForResizing() && !hasRareData())
         return;
     ensureElementRareData()->m_minimumSizeForResizing = size;
 }

 RenderStyle* Element::computedStyle(PseudoId pseudoElementSpecifier)
 {
     // FIXME: Find and use the renderer from the pseudo element instead of the actual element so that the 'length'
     // properties, which are only known by the renderer because it did the layout, will be correct and so that the
     // values returned for the ":selection" pseudo-element will be correct.
     if (RenderStyle* usedStyle = renderStyle()) {
         if (pseudoElementSpecifier) {
             RenderStyle* cachedPseudoStyle = usedStyle->getCachedPseudoStyle(pseudoElementSpecifier);
             return cachedPseudoStyle ? cachedPseudoStyle : usedStyle;
          } else
             return usedStyle;
     }

     if (!attached())
         // FIXME: Try to do better than this. Ensure that styleForElement() works for elements that are not in the
         // document tree and figure out when to destroy the computed style for such elements.
         return 0;

     ElementRareData* data = ensureElementRareData();
     if (!data->m_computedStyle)
         data->m_computedStyle = document()->styleForElementIgnoringPendingStylesheets(this);
     return pseudoElementSpecifier ? data->m_computedStyle->getCachedPseudoStyle(pseudoElementSpecifier) : data->m_computedStyle.get();
 }

 void Element::setStyleAffectedByEmpty()
 {
     ensureElementRareData()->setStyleAffectedByEmpty(true);
 }

 bool Element::styleAffectedByEmpty() const
 {
     return hasRareData() && elementRareData()->styleAffectedByEmpty();
 }

 void Element::setIsInCanvasSubtree(bool isInCanvasSubtree)
 {
     ensureElementRareData()->setIsInCanvasSubtree(isInCanvasSubtree);
 }

 bool Element::isInCanvasSubtree() const
 {
     return hasRareData() && elementRareData()->isInCanvasSubtree();
 }

 AtomicString Element::computeInheritedLanguage() const
 {
     const Node* n = this;
     AtomicString value;
     // The language property is inherited, so we iterate over the parents to find the first language.
     do {
         if (n->isElementNode()) {
             if (const ElementAttributeData* attributeData = static_cast<const Element*>(n)->attributeData()) {
                 // Spec: xml:lang takes precedence -- http://www.w3.org/TR/xhtml1/#C_7
                 if (const Attribute* attribute = attributeData->getAttributeItem(XMLNames::langAttr))
                     value = attribute->value();
                 else if (const Attribute* attribute = attributeData->getAttributeItem(HTMLNames::langAttr))
                     value = attribute->value();
             }
         } else if (n->isDocumentNode()) {
             // checking the MIME content-language
             value = static_cast<const Document*>(n)->contentLanguage();
         }

         n = n->parentNode();
     } while (n && value.isNull());

     return value;
 }

 Locale& Element::locale() const
 {
     return document()->getCachedLocale(computeInheritedLanguage());
 }

 void Element::cancelFocusAppearanceUpdate()
 {
     if (hasRareData())
         elementRareData()->setNeedsFocusAppearanceUpdateSoonAfterAttach(false);
     if (document()->focusedNode() == this)
         document()->cancelFocusAppearanceUpdate();
 }

 void Element::normalizeAttributes()
 {
     if (!hasAttrList())
         return;

     const ElementAttributeData* attributeData = updatedAttributeData();
     ASSERT(attributeData);

     for (size_t i = 0; i < attributeData->length(); ++i) {
         if (RefPtr<Attr> attr = attrIfExists(attributeData->attributeItem(i)->name()))
             attr->normalize();
     }
 }

 // ElementTraversal API
 Element* Element::firstElementChild() const
 {
     return WebCore::firstElementChild(this);
 }

 Element* Element::lastElementChild() const
 {
     Node* n = lastChild();
     while (n && !n->isElementNode())
         n = n->previousSibling();
     return static_cast<Element*>(n);
 }

 unsigned Element::childElementCount() const
 {
     unsigned count = 0;
     Node* n = firstChild();
     while (n) {
         count += n->isElementNode();
         n = n->nextSibling();
     }
     return count;
 }

 bool Element::shouldMatchReadOnlySelector() const
 {
     return false;
 }

 bool Element::shouldMatchReadWriteSelector() const
 {
     return false;
 }

 bool Element::webkitMatchesSelector(const String& selector, ExceptionCode& ec)
 {
     if (selector.isEmpty()) {
         ec = SYNTAX_ERR;
         return false;
     }

     SelectorQuery* selectorQuery = document()->selectorQueryCache()->add(selector, document(), ec);
     if (!selectorQuery)
         return false;
     return selectorQuery->matches(this);
 }

 DOMTokenList* Element::classList()
 {
     ElementRareData* data = ensureElementRareData();
     if (!data->m_classList)
         data->m_classList = ClassList::create(this);
     return data->m_classList.get();
 }

 DOMTokenList* Element::optionalClassList() const
 {
     if (!hasRareData())
         return 0;
     return elementRareData()->m_classList.get();
 }

 DOMStringMap* Element::dataset()
 {
     ElementRareData* data = ensureElementRareData();
     if (!data->m_datasetDOMStringMap)
         data->m_datasetDOMStringMap = DatasetDOMStringMap::create(this);
     return data->m_datasetDOMStringMap.get();
 }

 KURL Element::getURLAttribute(const QualifiedName& name) const
 {
 #if !ASSERT_DISABLED
     if (attributeData()) {
         if (const Attribute* attribute = getAttributeItem(name))
             ASSERT(isURLAttribute(*attribute));
     }
 #endif
     return document()->completeURL(stripLeadingAndTrailingHTMLSpaces(getAttribute(name)));
 }

 KURL Element::getNonEmptyURLAttribute(const QualifiedName& name) const
 {
 #if !ASSERT_DISABLED
     if (attributeData()) {
         if (const Attribute* attribute = getAttributeItem(name))
             ASSERT(isURLAttribute(*attribute));
     }
 #endif
     String value = stripLeadingAndTrailingHTMLSpaces(getAttribute(name));
     if (value.isEmpty())
         return KURL();
     return document()->completeURL(value);
 }

 int Element::getIntegralAttribute(const QualifiedName& attributeName) const
 {
     return getAttribute(attributeName).string().toInt();
 }

 void Element::setIntegralAttribute(const QualifiedName& attributeName, int value)
 {
     // FIXME: Need an AtomicString version of String::number.
     setAttribute(attributeName, String::number(value));
 }

 unsigned Element::getUnsignedIntegralAttribute(const QualifiedName& attributeName) const
 {
     return getAttribute(attributeName).string().toUInt();
 }

 void Element::setUnsignedIntegralAttribute(const QualifiedName& attributeName, unsigned value)
 {
     // FIXME: Need an AtomicString version of String::number.
     setAttribute(attributeName, String::number(value));
 }

 #if ENABLE(SVG)
 bool Element::childShouldCreateRenderer(const NodeRenderingContext& childContext) const
 {
     // Only create renderers for SVG elements whose parents are SVG elements, or for proper <svg xmlns="svgNS"> subdocuments.
     if (childContext.node()->isSVGElement())
         return childContext.node()->hasTagName(SVGNames::svgTag) || isSVGElement();

     return Node::childShouldCreateRenderer(childContext);
 }
 #endif

 #if ENABLE(FULLSCREEN_API)
 void Element::webkitRequestFullscreen()
 {
     document()->requestFullScreenForElement(this, ALLOW_KEYBOARD_INPUT, Document::EnforceIFrameAllowFullScreenRequirement);
 }

 void Element::webkitRequestFullScreen(unsigned short flags)
 {
     document()->requestFullScreenForElement(this, (flags | LEGACY_MOZILLA_REQUEST), Document::EnforceIFrameAllowFullScreenRequirement);
 }

 bool Element::containsFullScreenElement() const
 {
     return hasRareData() && elementRareData()->containsFullScreenElement();
 }

 void Element::setContainsFullScreenElement(bool flag)
 {
     ensureElementRareData()->setContainsFullScreenElement(flag);
     setNeedsStyleRecalc(SyntheticStyleChange);
 }

 static Element* parentCrossingFrameBoundaries(Element* element)
 {
     ASSERT(element);
     return element->parentElement() ? element->parentElement() : element->document()->ownerElement();
 }

 void Element::setContainsFullScreenElementOnAncestorsCrossingFrameBoundaries(bool flag)
 {
     Element* element = this;
     while ((element = parentCrossingFrameBoundaries(element)))
         element->setContainsFullScreenElement(flag);
 }
 #endif

 #if ENABLE(POINTER_LOCK)
 void Element::webkitRequestPointerLock()
 {
     if (document()->page())
         document()->page()->pointerLockController()->requestPointerLock(this);
 }
 #endif

 SpellcheckAttributeState Element::spellcheckAttributeState() const
 {
     const AtomicString& value = getAttribute(HTMLNames::spellcheckAttr);
     if (value == nullAtom)
         return SpellcheckAttributeDefault;
     if (equalIgnoringCase(value, "true") || equalIgnoringCase(value, ""))
         return SpellcheckAttributeTrue;
     if (equalIgnoringCase(value, "false"))
         return SpellcheckAttributeFalse;

     return SpellcheckAttributeDefault;
 }

 bool Element::isSpellCheckingEnabled() const
 {
     const Element* element = this;
     while (element) {
         switch (element->spellcheckAttributeState()) {
         case SpellcheckAttributeTrue:
             return true;
         case SpellcheckAttributeFalse:
             return false;
         case SpellcheckAttributeDefault:
             break;
         }

         ContainerNode* parent = const_cast<Element*>(element)->parentOrHostNode();
         if (parent && parent->isElementNode())
             element = toElement(parent);
         else if (parent && parent->isShadowRoot())
             element = toElement(parent->parentOrHostNode());
         else
             element = 0;
     }

     return true;
 }

 PassRefPtr<WebKitAnimationList> Element::webkitGetAnimations() const
 {
     if (!renderer())
         return 0;

     AnimationController* animController = renderer()->animation();

     if (!animController)
         return 0;

     return animController->animationsForRenderer(renderer());
 }

 RenderRegion* Element::renderRegion() const
 {
     if (renderer() && renderer()->isRenderRegion())
         return toRenderRegion(renderer());

     return 0;
 }

 #if ENABLE(CSS_REGIONS)

 const AtomicString& Element::webkitRegionOverset() const
 {
     document()->updateLayoutIgnorePendingStylesheets();

     DEFINE_STATIC_LOCAL(AtomicString, undefinedState, ("undefined"));
     if (!document()->cssRegionsEnabled() || !renderRegion())
         return undefinedState;

     switch (renderRegion()->regionState()) {
     case RenderRegion::RegionFit: {
         DEFINE_STATIC_LOCAL(AtomicString, fitState, ("fit"));
         return fitState;
     }
     case RenderRegion::RegionEmpty: {
         DEFINE_STATIC_LOCAL(AtomicString, emptyState, ("empty"));
         return emptyState;
     }
     case RenderRegion::RegionOverset: {
         DEFINE_STATIC_LOCAL(AtomicString, overflowState, ("overset"));
         return overflowState;
     }
     case RenderRegion::RegionUndefined:
         return undefinedState;
     }

     ASSERT_NOT_REACHED();
     return undefinedState;
 }

 Vector<RefPtr<Range> > Element::webkitGetRegionFlowRanges() const
 {
     document()->updateLayoutIgnorePendingStylesheets();

     Vector<RefPtr<Range> > rangeObjects;
     if (document()->cssRegionsEnabled() && renderer() && renderer()->isRenderRegion()) {
         RenderRegion* region = toRenderRegion(renderer());
         if (region->isValid())
             region->getRanges(rangeObjects);
     }

     return rangeObjects;
 }

 #endif

 #ifndef NDEBUG
 bool Element::fastAttributeLookupAllowed(const QualifiedName& name) const
 {
     if (name == HTMLNames::styleAttr)
         return false;

 #if ENABLE(SVG)
     if (isSVGElement())
         return !SVGElement::isAnimatableAttribute(name);
 #endif

     return true;
 }
 #endif

 #ifdef DUMP_NODE_STATISTICS
 bool Element::hasNamedNodeMap() const
 {
     return hasRareData() && elementRareData()->m_attributeMap;
 }
 #endif

 void Element::updateLabel(TreeScope* scope, const AtomicString& oldForAttributeValue, const AtomicString& newForAttributeValue)
 {
     ASSERT(hasTagName(labelTag));

     if (!inDocument())
         return;

     if (oldForAttributeValue == newForAttributeValue)
         return;

     if (!oldForAttributeValue.isEmpty())
         scope->removeLabel(oldForAttributeValue, static_cast<HTMLLabelElement*>(this));
     if (!newForAttributeValue.isEmpty())
         scope->addLabel(newForAttributeValue, static_cast<HTMLLabelElement*>(this));
 }

 void Element::willModifyAttribute(const QualifiedName& name, const AtomicString& oldValue, const AtomicString& newValue)
 {
     if (isIdAttributeName(name))
         updateId(oldValue, newValue);
     else if (name == HTMLNames::nameAttr)
         updateName(oldValue, newValue);
     else if (name == HTMLNames::forAttr && hasTagName(labelTag)) {
         TreeScope* scope = treeScope();
         if (scope->shouldCacheLabelsByForAttribute())
             updateLabel(scope, oldValue, newValue);
     }

 #if ENABLE(MUTATION_OBSERVERS)
     if (OwnPtr<MutationObserverInterestGroup> recipients = MutationObserverInterestGroup::createForAttributesMutation(this, name))
         recipients->enqueueMutationRecord(MutationRecord::createAttributes(this, name, oldValue));
 #endif

 #if ENABLE(UNDO_MANAGER)
     if (UndoManager::isRecordingAutomaticTransaction(this))
         UndoManager::addTransactionStep(AttrChangingDOMTransactionStep::create(this, name, oldValue, newValue));
 #endif

 #if ENABLE(INSPECTOR)
     InspectorInstrumentation::willModifyDOMAttr(document(), this, oldValue, newValue);
 #endif
 }

 void Element::didAddAttribute(const QualifiedName& name, const AtomicString& value)
 {
     attributeChanged(name, value);
     InspectorInstrumentation::didModifyDOMAttr(document(), this, name.localName(), value);
     dispatchSubtreeModifiedEvent();
 }

 void Element::didModifyAttribute(const QualifiedName& name, const AtomicString& value)
 {
     attributeChanged(name, value);
     InspectorInstrumentation::didModifyDOMAttr(document(), this, name.localName(), value);
     // Do not dispatch a DOMSubtreeModified event here; see bug 81141.
 }

 void Element::didRemoveAttribute(const QualifiedName& name)
 {
     attributeChanged(name, nullAtom);
     InspectorInstrumentation::didRemoveDOMAttr(document(), this, name.localName());
     dispatchSubtreeModifiedEvent();
 }


 void Element::updateNamedItemRegistration(const AtomicString& oldName, const AtomicString& newName)
 {
     if (!document()->isHTMLDocument())
         return;

     if (!oldName.isEmpty())
         static_cast<HTMLDocument*>(document())->removeNamedItem(oldName);

     if (!newName.isEmpty())
         static_cast<HTMLDocument*>(document())->addNamedItem(newName);
 }

 void Element::updateExtraNamedItemRegistration(const AtomicString& oldId, const AtomicString& newId)
 {
     if (!document()->isHTMLDocument())
         return;

     if (!oldId.isEmpty())
         static_cast<HTMLDocument*>(document())->removeExtraNamedItem(oldId);

     if (!newId.isEmpty())
         static_cast<HTMLDocument*>(document())->addExtraNamedItem(newId);
 }

 PassRefPtr<HTMLCollection> Element::ensureCachedHTMLCollection(CollectionType type)
 {
     return ensureElementRareData()->ensureCachedHTMLCollection(this, type);
 }

 PassRefPtr<HTMLCollection> ElementRareData::ensureCachedHTMLCollection(Element* element, CollectionType type)
 {
     if (!m_cachedCollections) {
         m_cachedCollections = adoptPtr(new CachedHTMLCollectionArray);
         for (unsigned i = 0; i < NumNodeCollectionTypes; i++)
             (*m_cachedCollections)[i] = 0;
     }

     if (HTMLCollection* collection = (*m_cachedCollections)[type - FirstNodeCollectionType])
         return collection;

     RefPtr<HTMLCollection> collection;
     if (type == TableRows) {
         ASSERT(element->hasTagName(tableTag));
         collection = HTMLTableRowsCollection::create(element);
     } else if (type == SelectOptions) {
         ASSERT(element->hasTagName(selectTag));
         collection = HTMLOptionsCollection::create(element);
     } else if (type == FormControls) {
         ASSERT(element->hasTagName(formTag) || element->hasTagName(fieldsetTag));
         collection = HTMLFormCollection::create(element);
 #if ENABLE(MICRODATA)
     } else if (type == ItemProperties) {
         collection = HTMLPropertiesCollection::create(element);
 #endif
     } else
         collection = HTMLCollection::create(element, type);
     (*m_cachedCollections)[type - FirstNodeCollectionType] = collection.get();
     return collection.release();
 }

 HTMLCollection* Element::cachedHTMLCollection(CollectionType type)
 {
     return hasRareData() ? elementRareData()->cachedHTMLCollection(type) : 0;
 }

 void Element::removeCachedHTMLCollection(HTMLCollection* collection, CollectionType type)
 {
     ASSERT(hasRareData());
     elementRareData()->removeCachedHTMLCollection(collection, type);
 }

 IntSize Element::savedLayerScrollOffset() const
 {
     return hasRareData() ? elementRareData()->m_savedLayerScrollOffset : IntSize();
 }

 void Element::setSavedLayerScrollOffset(const IntSize& size)
 {
     if (size.isZero() && !hasRareData())
         return;
     ensureElementRareData()->m_savedLayerScrollOffset = size;
 }

 PassRefPtr<Attr> Element::attrIfExists(const QualifiedName& name)
 {
     if (!hasAttrList())
         return 0;
     ASSERT(attributeData());
     return attributeData()->attrIfExists(this, name);
 }

 PassRefPtr<Attr> Element::ensureAttr(const QualifiedName& name)
 {
     ASSERT(attributeData());
     return attributeData()->ensureAttr(this, name);
 }

 bool Element::willRecalcStyle(StyleChange)
 {
     ASSERT(hasCustomCallbacks());
     return true;
 }

 void Element::didRecalcStyle(StyleChange)
 {
     ASSERT(hasCustomCallbacks());
 }


 PassRefPtr<RenderStyle> Element::customStyleForRenderer()
 {
     ASSERT(hasCustomCallbacks());
     return 0;
 }


 void Element::cloneAttributesFromElement(const Element& other)
 {
     if (const ElementAttributeData* attributeData = other.updatedAttributeData())
         mutableAttributeData()->cloneDataFrom(*attributeData, other, *this);
     else if (m_attributeData) {
         m_attributeData->clearAttributes(this);
         m_attributeData.clear();
     }
 }

 void Element::cloneDataFromElement(const Element& other)
 {
     cloneAttributesFromElement(other);
     copyNonAttributePropertiesFromElement(other);
 }

 void Element::createMutableAttributeData()
 {
     if (!m_attributeData)
         m_attributeData = ElementAttributeData::create();
     else
         m_attributeData = m_attributeData->makeMutableCopy();
 }

 void Element::reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
 {
     MemoryClassInfo info(memoryObjectInfo, this, WebCoreMemoryTypes::DOM);
     ContainerNode::reportMemoryUsage(memoryObjectInfo);
     info.addMember(m_tagName);
     info.addMember(m_attributeData);
 }

 } // namespace WebCore