/*
 * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
 * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
 * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
 * Copyright (C) 2008 Alp Toker <alp@atoker.com>
 * Copyright (C) Research In Motion Limited 2009. All rights reserved.
 * Copyright (C) 2011 Kris Jordan <krisjordan@gmail.com>
 *
 * 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 "FrameLoader.h"

#include "ApplicationCacheHost.h"
#include "BackForwardController.h"
#include "BeforeUnloadEvent.h"
#include "MemoryCache.h"
#include "CachedPage.h"
#include "CachedResourceLoader.h"
#include "Chrome.h"
#include "ChromeClient.h"
#include "Console.h"
#include "ContentSecurityPolicy.h"
#include "DOMImplementation.h"
#include "DOMWindow.h"
#include "Document.h"
#include "DocumentLoadTiming.h"
#include "DocumentLoader.h"
#include "Editor.h"
#include "EditorClient.h"
#include "Element.h"
#include "Event.h"
#include "EventNames.h"
#include "FloatRect.h"
#include "FormState.h"
#include "FormSubmission.h"
#include "Frame.h"
#include "FrameLoadRequest.h"
#include "FrameLoaderClient.h"
#include "FrameNetworkingContext.h"
#include "FrameTree.h"
#include "FrameView.h"
#include "HTMLAnchorElement.h"
#include "HTMLFormElement.h"
#include "HTMLNames.h"
#include "HTMLObjectElement.h"
#include "HTTPParsers.h"
#include "HistoryItem.h"
#include "InspectorController.h"
#include "InspectorInstrumentation.h"
#include "Logging.h"
#include "MIMETypeRegistry.h"
#include "MainResourceLoader.h"
#include "Page.h"
#include "PageCache.h"
#include "PageGroup.h"
#include "PageTransitionEvent.h"
#include "PluginData.h"
#include "PluginDatabase.h"
#include "PluginDocument.h"
#include "ProgressTracker.h"
#include "ResourceHandle.h"
#include "ResourceRequest.h"
#include "SchemeRegistry.h"
#include "ScrollAnimator.h"
#include "ScriptController.h"
#include "ScriptSourceCode.h"
#include "SecurityOrigin.h"
#include "SegmentedString.h"
#include "SerializedScriptValue.h"
#include "Settings.h"
#include "TextResourceDecoder.h"
#include "WindowFeatures.h"
#include "XMLDocumentParser.h"
#include <wtf/CurrentTime.h>
#include <wtf/StdLibExtras.h>
#include <wtf/text/CString.h>
#include <wtf/text/WTFString.h>

#if ENABLE(SHARED_WORKERS)
#include "SharedWorkerRepository.h"
#endif

#if ENABLE(SVG)
#include "SVGDocument.h"
#include "SVGLocatable.h"
#include "SVGNames.h"
#include "SVGPreserveAspectRatio.h"
#include "SVGSVGElement.h"
#include "SVGViewElement.h"
#include "SVGViewSpec.h"
#endif

#if ENABLE(WEB_ARCHIVE) || ENABLE(MHTML)
#include "Archive.h"
#include "ArchiveFactory.h"
#endif

namespace WebCore {

using namespace HTMLNames;

#if ENABLE(SVG)
using namespace SVGNames;
#endif

#if ENABLE(XHTMLMP)
static const char defaultAcceptHeader[] = "application/vnd.wap.xhtml+xml,application/xhtml+xml;profile='http://www.wapforum.org/xhtml',text/html,application/xml;q=0.9,*/*;q=0.8";
#else
static const char defaultAcceptHeader[] = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
#endif

static double storedTimeOfLastCompletedLoad;

bool isBackForwardLoadType(FrameLoadType type)
{
    switch (type) {
        case FrameLoadTypeStandard:
        case FrameLoadTypeReload:
        case FrameLoadTypeReloadFromOrigin:
        case FrameLoadTypeSame:
        case FrameLoadTypeRedirectWithLockedBackForwardList:
        case FrameLoadTypeReplace:
            return false;
        case FrameLoadTypeBack:
        case FrameLoadTypeForward:
        case FrameLoadTypeIndexedBackForward:
            return true;
    }
    ASSERT_NOT_REACHED();
    return false;
}

// This is not in the FrameLoader class to emphasize that it does not depend on
// private FrameLoader data, and to avoid increasing the number of public functions
// with access to private data.  Since only this .cpp file needs it, making it
// non-member lets us exclude it from the header file, thus keeping FrameLoader.h's
// API simpler.
//
// FIXME: isDocumentSandboxed should eventually replace isSandboxed.
static bool isDocumentSandboxed(Frame* frame, SandboxFlags mask)
{
    return frame->document() && frame->document()->securityOrigin()->isSandboxed(mask);
}

FrameLoader::FrameLoader(Frame* frame, FrameLoaderClient* client)
    : m_frame(frame)
    , m_client(client)
    , m_policyChecker(frame)
    , m_history(frame)
    , m_notifer(frame)
    , m_subframeLoader(frame)
    , m_icon(frame)
    , m_state(FrameStateCommittedPage)
    , m_loadType(FrameLoadTypeStandard)
    , m_delegateIsHandlingProvisionalLoadError(false)
    , m_quickRedirectComing(false)
    , m_sentRedirectNotification(false)
    , m_inStopAllLoaders(false)
    , m_isExecutingJavaScriptFormAction(false)
    , m_didCallImplicitClose(false)
    , m_wasUnloadEventEmitted(false)
    , m_pageDismissalEventBeingDispatched(false)
    , m_isComplete(false)
    , m_isLoadingMainResource(false)
    , m_hasReceivedFirstData(false)
    , m_needsClear(false)
    , m_checkTimer(this, &FrameLoader::checkTimerFired)
    , m_shouldCallCheckCompleted(false)
    , m_shouldCallCheckLoadComplete(false)
    , m_opener(0)
    , m_didPerformFirstNavigation(false)
    , m_loadingFromCachedPage(false)
    , m_suppressOpenerInNewFrame(false)
    , m_sandboxFlags(SandboxAll)
    , m_forcedSandboxFlags(SandboxNone)
{
}

FrameLoader::~FrameLoader()
{
    setOpener(0);

    HashSet<Frame*>::iterator end = m_openedFrames.end();
    for (HashSet<Frame*>::iterator it = m_openedFrames.begin(); it != end; ++it)
        (*it)->loader()->m_opener = 0;

    m_client->frameLoaderDestroyed();

    if (m_networkingContext)
        m_networkingContext->invalidate();
}

void FrameLoader::init()
{
    // Propagate sandbox attributes to this Frameloader and its descendants.
    // This needs to be done early, so that an initial document gets correct sandbox flags in its SecurityOrigin.
    updateSandboxFlags();

    // This somewhat odd set of steps gives the frame an initial empty document.
    // It would be better if this could be done with even fewer steps.
    m_stateMachine.advanceTo(FrameLoaderStateMachine::CreatingInitialEmptyDocument);
    setPolicyDocumentLoader(m_client->createDocumentLoader(ResourceRequest(KURL(ParsedURLString, "")), SubstituteData()).get());
    setProvisionalDocumentLoader(m_policyDocumentLoader.get());
    setState(FrameStateProvisional);
    m_provisionalDocumentLoader->setResponse(ResourceResponse(KURL(), "text/html", 0, String(), String()));
    m_provisionalDocumentLoader->finishedLoading();
    ASSERT(!m_frame->document());
    m_documentLoader->writer()->begin(KURL(), false);
    m_documentLoader->writer()->end();
    m_frame->document()->cancelParsing();
    m_stateMachine.advanceTo(FrameLoaderStateMachine::DisplayingInitialEmptyDocument);
    m_didCallImplicitClose = true;

    m_networkingContext = m_client->createNetworkingContext();
}

void FrameLoader::setDefersLoading(bool defers)
{
    if (m_documentLoader)
        m_documentLoader->setDefersLoading(defers);
    if (m_provisionalDocumentLoader)
        m_provisionalDocumentLoader->setDefersLoading(defers);
    if (m_policyDocumentLoader)
        m_policyDocumentLoader->setDefersLoading(defers);
    history()->setDefersLoading(defers);

    if (!defers) {
        m_frame->navigationScheduler()->startTimer();
        startCheckCompleteTimer();
    }
}

void FrameLoader::changeLocation(PassRefPtr<SecurityOrigin> securityOrigin, const KURL& url, const String& referrer, bool lockHistory, bool lockBackForwardList, bool refresh)
{
    RefPtr<Frame> protect(m_frame);
    urlSelected(FrameLoadRequest(securityOrigin, ResourceRequest(url, referrer, refresh ? ReloadIgnoringCacheData : UseProtocolCachePolicy), "_self"),
        0, lockHistory, lockBackForwardList, SendReferrer, ReplaceDocumentIfJavaScriptURL);
}

void FrameLoader::urlSelected(const KURL& url, const String& passedTarget, PassRefPtr<Event> triggeringEvent, bool lockHistory, bool lockBackForwardList, ReferrerPolicy referrerPolicy)
{
    urlSelected(FrameLoadRequest(m_frame->document()->securityOrigin(), ResourceRequest(url), passedTarget),
        triggeringEvent, lockHistory, lockBackForwardList, referrerPolicy, DoNotReplaceDocumentIfJavaScriptURL);
}

// The shouldReplaceDocumentIfJavaScriptURL parameter will go away when the FIXME to eliminate the
// corresponding parameter from ScriptController::executeIfJavaScriptURL() is addressed.
void FrameLoader::urlSelected(const FrameLoadRequest& passedRequest, PassRefPtr<Event> triggeringEvent, bool lockHistory, bool lockBackForwardList, ReferrerPolicy referrerPolicy, ShouldReplaceDocumentIfJavaScriptURL shouldReplaceDocumentIfJavaScriptURL)
{
    ASSERT(!m_suppressOpenerInNewFrame);

    FrameLoadRequest frameRequest(passedRequest);

    if (m_frame->script()->executeIfJavaScriptURL(frameRequest.resourceRequest().url(), shouldReplaceDocumentIfJavaScriptURL))
        return;

    if (frameRequest.frameName().isEmpty())
        frameRequest.setFrameName(m_frame->document()->baseTarget());

    if (referrerPolicy == NoReferrer)
        m_suppressOpenerInNewFrame = true;
    if (frameRequest.resourceRequest().httpReferrer().isEmpty())
        frameRequest.resourceRequest().setHTTPReferrer(m_outgoingReferrer);
    addHTTPOriginIfNeeded(frameRequest.resourceRequest(), outgoingOrigin());

    loadFrameRequest(frameRequest, lockHistory, lockBackForwardList, triggeringEvent, 0, referrerPolicy);

    m_suppressOpenerInNewFrame = false;
}

void FrameLoader::submitForm(PassRefPtr<FormSubmission> submission)
{
    ASSERT(submission->method() == FormSubmission::PostMethod || submission->method() == FormSubmission::GetMethod);

    // FIXME: Find a good spot for these.
    ASSERT(submission->data());
    ASSERT(submission->state());
    ASSERT(submission->state()->sourceFrame() == m_frame);
    
    if (!m_frame->page())
        return;
    
    if (submission->action().isEmpty())
        return;

    if (isDocumentSandboxed(m_frame, SandboxForms))
        return;

    if (protocolIsJavaScript(submission->action())) {
        m_isExecutingJavaScriptFormAction = true;
        m_frame->script()->executeIfJavaScriptURL(submission->action(), DoNotReplaceDocumentIfJavaScriptURL);
        m_isExecutingJavaScriptFormAction = false;
        return;
    }

    Frame* targetFrame = m_frame->tree()->find(submission->target());
    if (!shouldAllowNavigation(targetFrame))
        return;
    if (!targetFrame) {
        if (!DOMWindow::allowPopUp(m_frame) && !ScriptController::processingUserGesture())
            return;

        targetFrame = m_frame;
    } else
        submission->clearTarget();

    if (!targetFrame->page())
        return;

    // FIXME: We'd like to remove this altogether and fix the multiple form submission issue another way.

    // We do not want to submit more than one form from the same page, nor do we want to submit a single
    // form more than once. This flag prevents these from happening; not sure how other browsers prevent this.
    // The flag is reset in each time we start handle a new mouse or key down event, and
    // also in setView since this part may get reused for a page from the back/forward cache.
    // The form multi-submit logic here is only needed when we are submitting a form that affects this frame.

    // FIXME: Frame targeting is only one of the ways the submission could end up doing something other
    // than replacing this frame's content, so this check is flawed. On the other hand, the check is hardly
    // needed any more now that we reset m_submittedFormURL on each mouse or key down event.

    if (m_frame->tree()->isDescendantOf(targetFrame)) {
        if (m_submittedFormURL == submission->action())
            return;
        m_submittedFormURL = submission->action();
    }

    submission->data()->generateFiles(m_frame->document());
    submission->setReferrer(m_outgoingReferrer);
    submission->setOrigin(outgoingOrigin());

    targetFrame->navigationScheduler()->scheduleFormSubmission(submission);
}

void FrameLoader::stopLoading(UnloadEventPolicy unloadEventPolicy)
{
    if (m_frame->document() && m_frame->document()->parser())
        m_frame->document()->parser()->stopParsing();

    if (unloadEventPolicy != UnloadEventPolicyNone) {
        if (m_frame->document()) {
            if (m_didCallImplicitClose && !m_wasUnloadEventEmitted) {
                Node* currentFocusedNode = m_frame->document()->focusedNode();
                if (currentFocusedNode)
                    currentFocusedNode->aboutToUnload();
                m_pageDismissalEventBeingDispatched = true;
                if (m_frame->domWindow()) {
                    if (unloadEventPolicy == UnloadEventPolicyUnloadAndPageHide)
                        m_frame->domWindow()->dispatchEvent(PageTransitionEvent::create(eventNames().pagehideEvent, m_frame->document()->inPageCache()), m_frame->document());
                    if (!m_frame->document()->inPageCache()) {
                        RefPtr<Event> unloadEvent(Event::create(eventNames().unloadEvent, false, false));
                        // The DocumentLoader (and thus its DocumentLoadTiming) might get destroyed
                        // while dispatching the event, so protect it to prevent writing the end
                        // time into freed memory.
                        RefPtr<DocumentLoader> documentLoader = m_provisionalDocumentLoader;
                        if (documentLoader && !documentLoader->timing()->unloadEventStart && !documentLoader->timing()->unloadEventEnd) {
                            DocumentLoadTiming* timing = documentLoader->timing();
                            ASSERT(timing->navigationStart);
                            m_frame->domWindow()->dispatchTimedEvent(unloadEvent, m_frame->domWindow()->document(), &timing->unloadEventStart, &timing->unloadEventEnd);
                        } else
                            m_frame->domWindow()->dispatchEvent(unloadEvent, m_frame->domWindow()->document());
                    }
                }
                m_pageDismissalEventBeingDispatched = false;
                if (m_frame->document())
                    m_frame->document()->updateStyleIfNeeded();
                m_wasUnloadEventEmitted = true;
            }
        }

        // Dispatching the unload event could have made m_frame->document() null.
        if (m_frame->document() && !m_frame->document()->inPageCache()) {
            // Don't remove event listeners from a transitional empty document (see bug 28716 for more information).
            bool keepEventListeners = m_stateMachine.isDisplayingInitialEmptyDocument() && m_provisionalDocumentLoader
                && m_frame->document()->securityOrigin()->isSecureTransitionTo(m_provisionalDocumentLoader->url());

            if (!keepEventListeners)
                m_frame->document()->removeAllEventListeners();
        }
    }

    m_isComplete = true; // to avoid calling completed() in finishedParsing()
    m_isLoadingMainResource = false;
    m_didCallImplicitClose = true; // don't want that one either

    if (m_frame->document() && m_frame->document()->parsing()) {
        finishedParsing();
        m_frame->document()->setParsing(false);
    }

    m_hasReceivedFirstData = true;

    if (Document* doc = m_frame->document()) {
        // FIXME: HTML5 doesn't tell us to set the state to complete when aborting, but we do anyway to match legacy behavior.
        // http://www.w3.org/Bugs/Public/show_bug.cgi?id=10537
        doc->setReadyState(Document::Complete);

#if ENABLE(DATABASE)
        doc->stopDatabases(0);
#endif
    }

    // FIXME: This will cancel redirection timer, which really needs to be restarted when restoring the frame from b/f cache.
    m_frame->navigationScheduler()->cancel();
}

void FrameLoader::stop()
{
    // http://bugs.webkit.org/show_bug.cgi?id=10854
    // The frame's last ref may be removed and it will be deleted by checkCompleted().
    RefPtr<Frame> protector(m_frame);

    if (DocumentParser* parser = m_frame->document()->parser()) {
        parser->stopParsing();
        parser->finish();
    }
    
    icon()->stopLoader();
}

bool FrameLoader::closeURL()
{
    history()->saveDocumentState();
    
    // Should only send the pagehide event here if the current document exists and has not been placed in the page cache.    
    Document* currentDocument = m_frame->document();
    stopLoading(currentDocument && !currentDocument->inPageCache() ? UnloadEventPolicyUnloadAndPageHide : UnloadEventPolicyUnloadOnly);
    
    m_frame->editor()->clearUndoRedoOperations();
    return true;
}

bool FrameLoader::didOpenURL()
{
    if (m_frame->navigationScheduler()->redirectScheduledDuringLoad()) {
        // A redirect was scheduled before the document was created.
        // This can happen when one frame changes another frame's location.
        return false;
    }

    m_frame->navigationScheduler()->cancel();
    m_frame->editor()->clearLastEditCommand();

    m_isComplete = false;
    m_isLoadingMainResource = true;
    m_didCallImplicitClose = false;

    // If we are still in the process of initializing an empty document then
    // its frame is not in a consistent state for rendering, so avoid setJSStatusBarText
    // since it may cause clients to attempt to render the frame.
    if (!m_stateMachine.creatingInitialEmptyDocument()) {
        if (DOMWindow* window = m_frame->existingDOMWindow()) {
            window->setStatus(String());
            window->setDefaultStatus(String());
        }
    }
    m_hasReceivedFirstData = false;

    started();

    return true;
}

void FrameLoader::didExplicitOpen()
{
    m_isComplete = false;
    m_didCallImplicitClose = false;

    // Calling document.open counts as committing the first real document load.
    if (!m_stateMachine.committedFirstRealDocumentLoad())
        m_stateMachine.advanceTo(FrameLoaderStateMachine::DisplayingInitialEmptyDocumentPostCommit);
    
    // Prevent window.open(url) -- eg window.open("about:blank") -- from blowing away results
    // from a subsequent window.document.open / window.document.write call. 
    // Canceling redirection here works for all cases because document.open 
    // implicitly precedes document.write.
    m_frame->navigationScheduler()->cancel();
}


void FrameLoader::cancelAndClear()
{
    m_frame->navigationScheduler()->cancel();

    if (!m_isComplete)
        closeURL();

    clear(false);
    m_frame->script()->updatePlatformScriptObjects();
}

void FrameLoader::clear(bool clearWindowProperties, bool clearScriptObjects, bool clearFrameView)
{
    m_frame->editor()->clear();

    if (!m_needsClear)
        return;
    m_needsClear = false;
    
    if (!m_frame->document()->inPageCache()) {
        m_frame->document()->cancelParsing();
        m_frame->document()->stopActiveDOMObjects();
        if (m_frame->document()->attached()) {
            m_frame->document()->willRemove();
            m_frame->document()->detach();
            
            m_frame->document()->removeFocusedNodeOfSubtree(m_frame->document());
        }
    }

    // Do this after detaching the document so that the unload event works.
    if (clearWindowProperties) {
        m_frame->clearDOMWindow();
        m_frame->script()->clearWindowShell(m_frame->document()->inPageCache());
    }

    m_frame->selection()->clear();
    m_frame->eventHandler()->clear();
    if (clearFrameView && m_frame->view())
        m_frame->view()->clear();

    // Do not drop the document before the ScriptController and view are cleared
    // as some destructors might still try to access the document.
    m_frame->setDocument(0);

    m_subframeLoader.clear();

    if (clearScriptObjects)
        m_frame->script()->clearScriptObjects();

    m_frame->navigationScheduler()->clear();

    m_checkTimer.stop();
    m_shouldCallCheckCompleted = false;
    m_shouldCallCheckLoadComplete = false;

    if (m_stateMachine.isDisplayingInitialEmptyDocument() && m_stateMachine.committedFirstRealDocumentLoad())
        m_stateMachine.advanceTo(FrameLoaderStateMachine::CommittedFirstRealLoad);
}

void FrameLoader::receivedFirstData()
{
    KURL workingURL = activeDocumentLoader()->documentURL();
#if ENABLE(WEB_ARCHIVE) || ENABLE(MHTML)
    if (m_archive)
        workingURL = m_archive->mainResource()->url();
#endif

    activeDocumentLoader()->writer()->begin(workingURL, false);
    activeDocumentLoader()->writer()->setDocumentWasLoadedAsPartOfNavigation();

    dispatchDidCommitLoad();
    dispatchDidClearWindowObjectsInAllWorlds();
    
    if (m_documentLoader) {
        StringWithDirection ptitle = m_documentLoader->title();
        // If we have a title let the WebView know about it.
        if (!ptitle.isNull())
            m_client->dispatchDidReceiveTitle(ptitle);
    }

    m_hasReceivedFirstData = true;

    if (!m_documentLoader)
        return;
    if (m_frame->document()->isViewSource())
        return;

    double delay;
    String url;
    if (!parseHTTPRefresh(m_documentLoader->response().httpHeaderField("Refresh"), false, delay, url))
        return;
    if (url.isEmpty())
        url = m_frame->document()->url().string();
    else
        url = m_frame->document()->completeURL(url).string();

    m_frame->navigationScheduler()->scheduleRedirect(delay, url);
}

void FrameLoader::setOutgoingReferrer(const KURL& url)
{
    m_outgoingReferrer = url.strippedForUseAsReferrer();
}

void FrameLoader::didBeginDocument(bool dispatch)
{
    m_needsClear = true;
    m_isComplete = false;
    m_didCallImplicitClose = false;
    m_isLoadingMainResource = true;
    m_frame->document()->setReadyState(Document::Loading);

    if (m_pendingStateObject) {
        m_frame->document()->statePopped(m_pendingStateObject.get());
        m_pendingStateObject.clear();
    }

    if (dispatch)
        dispatchDidClearWindowObjectsInAllWorlds();

    updateFirstPartyForCookies();

    Settings* settings = m_frame->document()->settings();
    m_frame->document()->cachedResourceLoader()->setAutoLoadImages(settings && settings->loadsImagesAutomatically());

    if (m_documentLoader) {
        String dnsPrefetchControl = m_documentLoader->response().httpHeaderField("X-DNS-Prefetch-Control");
        if (!dnsPrefetchControl.isEmpty())
            m_frame->document()->parseDNSPrefetchControlHeader(dnsPrefetchControl);

        String contentSecurityPolicy = m_documentLoader->response().httpHeaderField("X-WebKit-CSP");
        if (!contentSecurityPolicy.isEmpty())
            m_frame->document()->contentSecurityPolicy()->didReceiveHeader(contentSecurityPolicy, ContentSecurityPolicy::EnforcePolicy);

        String reportOnlyContentSecurityPolicy = m_documentLoader->response().httpHeaderField("X-WebKit-CSP-Report-Only");
        if (!contentSecurityPolicy.isEmpty())
            m_frame->document()->contentSecurityPolicy()->didReceiveHeader(reportOnlyContentSecurityPolicy, ContentSecurityPolicy::ReportOnly);
    }

    history()->restoreDocumentState();
}

void FrameLoader::didEndDocument()
{
    m_isLoadingMainResource = false;
}

void FrameLoader::finishedParsing()
{
    m_frame->injectUserScripts(InjectAtDocumentEnd);

    if (m_stateMachine.creatingInitialEmptyDocument())
        return;

    // This can be called from the Frame's destructor, in which case we shouldn't protect ourselves
    // because doing so will cause us to re-enter the destructor when protector goes out of scope.
    // Null-checking the FrameView indicates whether or not we're in the destructor.
    RefPtr<Frame> protector = m_frame->view() ? m_frame : 0;

    m_client->dispatchDidFinishDocumentLoad();

    checkCompleted();

    if (!m_frame->view())
        return; // We are being destroyed by something checkCompleted called.

    // Check if the scrollbars are really needed for the content.
    // If not, remove them, relayout, and repaint.
    m_frame->view()->restoreScrollbar();
    m_frame->view()->scrollToFragment(m_frame->document()->url());
}

void FrameLoader::loadDone()
{
    checkCompleted();
}

bool FrameLoader::allChildrenAreComplete() const
{
    for (Frame* child = m_frame->tree()->firstChild(); child; child = child->tree()->nextSibling()) {
        if (!child->loader()->m_isComplete)
            return false;
    }
    return true;
}

bool FrameLoader::allAncestorsAreComplete() const
{
    for (Frame* ancestor = m_frame; ancestor; ancestor = ancestor->tree()->parent()) {
        if (!ancestor->loader()->m_isComplete)
            return false;
    }
    return true;
}

void FrameLoader::checkCompleted()
{
    m_shouldCallCheckCompleted = false;

    if (m_frame->view())
        m_frame->view()->checkStopDelayingDeferredRepaints();

    // Have we completed before?
    if (m_isComplete)
        return;

    // Are we still parsing?
    if (m_frame->document()->parsing())
        return;

    // Still waiting for images/scripts?
    if (m_frame->document()->cachedResourceLoader()->requestCount())
        return;

    // Still waiting for elements that don't go through a FrameLoader?
    if (m_frame->document()->isDelayingLoadEvent())
        return;

    // Any frame that hasn't completed yet?
    if (!allChildrenAreComplete())
        return;

    // OK, completed.
    m_isComplete = true;
    m_frame->document()->setReadyState(Document::Complete);

    RefPtr<Frame> protect(m_frame);
    checkCallImplicitClose(); // if we didn't do it before

    m_frame->navigationScheduler()->startTimer();

    completed();
    if (m_frame->page())
        checkLoadComplete();
}

void FrameLoader::checkTimerFired(Timer<FrameLoader>*)
{
    if (Page* page = m_frame->page()) {
        if (page->defersLoading())
            return;
    }
    if (m_shouldCallCheckCompleted)
        checkCompleted();
    if (m_shouldCallCheckLoadComplete)
        checkLoadComplete();
}

void FrameLoader::startCheckCompleteTimer()
{
    if (!(m_shouldCallCheckCompleted || m_shouldCallCheckLoadComplete))
        return;
    if (m_checkTimer.isActive())
        return;
    m_checkTimer.startOneShot(0);
}

void FrameLoader::scheduleCheckCompleted()
{
    m_shouldCallCheckCompleted = true;
    startCheckCompleteTimer();
}

void FrameLoader::scheduleCheckLoadComplete()
{
    m_shouldCallCheckLoadComplete = true;
    startCheckCompleteTimer();
}

void FrameLoader::checkCallImplicitClose()
{
    if (m_didCallImplicitClose || m_frame->document()->parsing() || m_frame->document()->isDelayingLoadEvent())
        return;

    if (!allChildrenAreComplete())
        return; // still got a frame running -> too early

    m_didCallImplicitClose = true;
    m_wasUnloadEventEmitted = false;
    m_frame->document()->implicitClose();
}

void FrameLoader::loadURLIntoChildFrame(const KURL& url, const String& referer, Frame* childFrame)
{
    ASSERT(childFrame);

#if ENABLE(WEB_ARCHIVE) || ENABLE(MHTML)
    RefPtr<Archive> subframeArchive = activeDocumentLoader()->popArchiveForSubframe(childFrame->tree()->uniqueName(), url);    
    if (subframeArchive) {
        childFrame->loader()->loadArchive(subframeArchive.release());
        return;
    }
#endif // ENABLE(WEB_ARCHIVE)

    HistoryItem* parentItem = history()->currentItem();
    // If we're moving in the back/forward list, we might want to replace the content
    // of this child frame with whatever was there at that point.
    if (parentItem && parentItem->children().size() && isBackForwardLoadType(loadType())) {
        HistoryItem* childItem = parentItem->childItemWithTarget(childFrame->tree()->uniqueName());
        if (childItem) {
            childFrame->loader()->loadDifferentDocumentItem(childItem, loadType());
            return;
        }
    }

    childFrame->loader()->loadURL(url, referer, String(), false, FrameLoadTypeRedirectWithLockedBackForwardList, 0, 0);
}

#if ENABLE(WEB_ARCHIVE) || ENABLE(MHTML)
void FrameLoader::loadArchive(PassRefPtr<Archive> archive)
{
    m_archive = archive;
    
    ArchiveResource* mainResource = m_archive->mainResource();
    ASSERT(mainResource);
    if (!mainResource)
        return;
        
    SubstituteData substituteData(mainResource->data(), mainResource->mimeType(), mainResource->textEncoding(), KURL());
    
    ResourceRequest request(mainResource->url());
#if PLATFORM(MAC)
    request.applyWebArchiveHackForMail();
#endif

    RefPtr<DocumentLoader> documentLoader = m_client->createDocumentLoader(request, substituteData);
    documentLoader->addAllArchiveResources(m_archive.get());
    load(documentLoader.get());
}
#endif // ENABLE(WEB_ARCHIVE) || ENABLE(MHTML)

ObjectContentType FrameLoader::defaultObjectContentType(const KURL& url, const String& mimeTypeIn, bool shouldPreferPlugInsForImages)
{
    String mimeType = mimeTypeIn;
    String extension = url.path().substring(url.path().reverseFind('.') + 1);

    // We don't use MIMETypeRegistry::getMIMETypeForPath() because it returns "application/octet-stream" upon failure
    if (mimeType.isEmpty())
        mimeType = MIMETypeRegistry::getMIMETypeForExtension(extension);

#if !PLATFORM(MAC) && !PLATFORM(CHROMIUM) && !PLATFORM(EFL) // Mac has no PluginDatabase, nor does Chromium or EFL
    if (mimeType.isEmpty())
        mimeType = PluginDatabase::installedPlugins()->MIMETypeForExtension(extension);
#endif

    if (mimeType.isEmpty())
        return ObjectContentFrame; // Go ahead and hope that we can display the content.

#if !PLATFORM(MAC) && !PLATFORM(CHROMIUM) && !PLATFORM(EFL) // Mac has no PluginDatabase, nor does Chromium or EFL
    bool plugInSupportsMIMEType = PluginDatabase::installedPlugins()->isMIMETypeRegistered(mimeType);
#else
    bool plugInSupportsMIMEType = false;
#endif

    if (MIMETypeRegistry::isSupportedImageMIMEType(mimeType))
        return shouldPreferPlugInsForImages && plugInSupportsMIMEType ? WebCore::ObjectContentNetscapePlugin : WebCore::ObjectContentImage;

    if (plugInSupportsMIMEType)
        return WebCore::ObjectContentNetscapePlugin;

    if (MIMETypeRegistry::isSupportedNonImageMIMEType(mimeType))
        return WebCore::ObjectContentFrame;

    return WebCore::ObjectContentNone;
}

String FrameLoader::outgoingReferrer() const
{
    return m_outgoingReferrer;
}

String FrameLoader::outgoingOrigin() const
{
    return m_frame->document()->securityOrigin()->toString();
}

bool FrameLoader::isMixedContent(SecurityOrigin* context, const KURL& url)
{
    if (context->protocol() != "https")
        return false;  // We only care about HTTPS security origins.

    if (!url.isValid() || SchemeRegistry::shouldTreatURLSchemeAsSecure(url.protocol()))
        return false;  // Loading these protocols is secure.

    return true;
}

bool FrameLoader::checkIfDisplayInsecureContent(SecurityOrigin* context, const KURL& url)
{
    if (!isMixedContent(context, url))
        return true;

    Settings* settings = m_frame->settings();
    bool allowed = m_client->allowDisplayingInsecureContent(settings && settings->allowDisplayOfInsecureContent(), context, url);
    String message = (allowed ? emptyString() : "[blocked] ") + "The page at " +
        m_frame->document()->url().string() + " displayed insecure content from " + url.string() + ".\n";
        
    m_frame->domWindow()->console()->addMessage(HTMLMessageSource, LogMessageType, WarningMessageLevel, message, 1, String());

    if (allowed)
        m_client->didDisplayInsecureContent();

    return allowed;
}

bool FrameLoader::checkIfRunInsecureContent(SecurityOrigin* context, const KURL& url)
{
    if (!isMixedContent(context, url))
        return true;

    Settings* settings = m_frame->settings();
    bool allowed = m_client->allowRunningInsecureContent(settings && settings->allowRunningOfInsecureContent(), context, url);
    String message = (allowed ? emptyString() : "[blocked] ") + "The page at " +
        m_frame->document()->url().string() + " ran insecure content from " + url.string() + ".\n";
       
    m_frame->domWindow()->console()->addMessage(HTMLMessageSource, LogMessageType, WarningMessageLevel, message, 1, String());

    if (allowed)
        m_client->didRunInsecureContent(context, url);

    return allowed;
}

Frame* FrameLoader::opener()
{
    return m_opener;
}

void FrameLoader::setOpener(Frame* opener)
{
    if (m_opener)
        m_opener->loader()->m_openedFrames.remove(m_frame);
    if (opener)
        opener->loader()->m_openedFrames.add(m_frame);
    m_opener = opener;

    if (m_frame->document()) {
        m_frame->document()->initSecurityContext();
        m_frame->domWindow()->setSecurityOrigin(m_frame->document()->securityOrigin());
    }
}

// FIXME: This does not belong in FrameLoader!
void FrameLoader::handleFallbackContent()
{
    HTMLFrameOwnerElement* owner = m_frame->ownerElement();
    if (!owner || !owner->hasTagName(objectTag))
        return;
    static_cast<HTMLObjectElement*>(owner)->renderFallbackContent();
}

void FrameLoader::provisionalLoadStarted()
{
    if (m_stateMachine.firstLayoutDone())
        m_stateMachine.advanceTo(FrameLoaderStateMachine::CommittedFirstRealLoad);
    m_frame->navigationScheduler()->cancel(true);
    m_client->provisionalLoadStarted();
}

void FrameLoader::resetMultipleFormSubmissionProtection()
{
    m_submittedFormURL = KURL();
}

void FrameLoader::willSetEncoding()
{
    if (!m_hasReceivedFirstData)
        receivedFirstData();
}

void FrameLoader::updateFirstPartyForCookies()
{
    if (m_frame->tree()->parent())
        setFirstPartyForCookies(m_frame->tree()->parent()->document()->firstPartyForCookies());
    else
        setFirstPartyForCookies(m_frame->document()->url());
}

void FrameLoader::setFirstPartyForCookies(const KURL& url)
{
    for (Frame* frame = m_frame; frame; frame = frame->tree()->traverseNext(m_frame))
        frame->document()->setFirstPartyForCookies(url);
}

// This does the same kind of work that didOpenURL does, except it relies on the fact
// that a higher level already checked that the URLs match and the scrolling is the right thing to do.
void FrameLoader::loadInSameDocument(const KURL& url, SerializedScriptValue* stateObject, bool isNewNavigation)
{
    // If we have a state object, we cannot also be a new navigation.
    ASSERT(!stateObject || (stateObject && !isNewNavigation));

    // Update the data source's request with the new URL to fake the URL change
    KURL oldURL = m_frame->document()->url();
    m_frame->document()->setURL(url);
    documentLoader()->replaceRequestURLForSameDocumentNavigation(url);
    if (isNewNavigation && !shouldTreatURLAsSameAsCurrent(url) && !stateObject) {
        // NB: must happen after replaceRequestURLForSameDocumentNavigation(), since we add 
        // based on the current request. Must also happen before we openURL and displace the 
        // scroll position, since adding the BF item will save away scroll state.
        
        // NB2:  If we were loading a long, slow doc, and the user anchor nav'ed before
        // it was done, currItem is now set the that slow doc, and prevItem is whatever was
        // before it.  Adding the b/f item will bump the slow doc down to prevItem, even
        // though its load is not yet done.  I think this all works out OK, for one because
        // we have already saved away the scroll and doc state for the long slow load,
        // but it's not an obvious case.

        history()->updateBackForwardListForFragmentScroll();
    }
    
    bool hashChange = equalIgnoringFragmentIdentifier(url, oldURL) && url.fragmentIdentifier() != oldURL.fragmentIdentifier();
    
    history()->updateForSameDocumentNavigation();

    // If we were in the autoscroll/panScroll mode we want to stop it before following the link to the anchor
    if (hashChange)
        m_frame->eventHandler()->stopAutoscrollTimer();
    
    // It's important to model this as a load that starts and immediately finishes.
    // Otherwise, the parent frame may think we never finished loading.
    started();

    // We need to scroll to the fragment whether or not a hash change occurred, since
    // the user might have scrolled since the previous navigation.
    if (FrameView* view = m_frame->view())
        view->scrollToFragment(url);
    
    m_isComplete = false;
    checkCompleted();

    if (isNewNavigation) {
        // This will clear previousItem from the rest of the frame tree that didn't
        // doing any loading. We need to make a pass on this now, since for anchor nav
        // we'll not go through a real load and reach Completed state.
        checkLoadComplete();
    }

    m_client->dispatchDidNavigateWithinPage();

    m_frame->document()->statePopped(stateObject ? stateObject : SerializedScriptValue::nullValue());
    m_client->dispatchDidPopStateWithinPage();
    
    if (hashChange) {
        m_frame->document()->enqueueHashchangeEvent(oldURL, url);
        m_client->dispatchDidChangeLocationWithinPage();
    }
    
    // FrameLoaderClient::didFinishLoad() tells the internal load delegate the load finished with no error
    m_client->didFinishLoad();
}

bool FrameLoader::isComplete() const
{
    return m_isComplete;
}

void FrameLoader::completed()
{
    RefPtr<Frame> protect(m_frame);

    for (Frame* descendant = m_frame->tree()->traverseNext(m_frame); descendant; descendant = descendant->tree()->traverseNext(m_frame))
        descendant->navigationScheduler()->startTimer();

    if (Frame* parent = m_frame->tree()->parent())
        parent->loader()->checkCompleted();

    if (m_frame->view())
        m_frame->view()->maintainScrollPositionAtAnchor(0);
}

void FrameLoader::started()
{
    for (Frame* frame = m_frame; frame; frame = frame->tree()->parent())
        frame->loader()->m_isComplete = false;
}

void FrameLoader::prepareForLoadStart()
{
    if (Page* page = m_frame->page())
        page->progress()->progressStarted(m_frame);
    m_client->dispatchDidStartProvisionalLoad();
}

void FrameLoader::setupForReplace()
{
    setState(FrameStateProvisional);
    m_provisionalDocumentLoader = m_documentLoader;
    m_documentLoader = 0;
    detachChildren();
}

// This is a hack to allow keep navigation to http/https feeds working. To remove this
// we need to introduce new API akin to registerURLSchemeAsLocal, that registers a
// protocols navigation policy.
static bool isFeedWithNestedProtocolInHTTPFamily(const KURL& url)
{
    const String& urlString = url.string();
    if (!urlString.startsWith("feed", false))
        return false;

    return urlString.startsWith("feed://", false) 
        || urlString.startsWith("feed:http:", false) || urlString.startsWith("feed:https:", false)
        || urlString.startsWith("feeds:http:", false) || urlString.startsWith("feeds:https:", false)
        || urlString.startsWith("feedsearch:http:", false) || urlString.startsWith("feedsearch:https:", false);
}

void FrameLoader::loadFrameRequest(const FrameLoadRequest& request, bool lockHistory, bool lockBackForwardList,
    PassRefPtr<Event> event, PassRefPtr<FormState> formState, ReferrerPolicy referrerPolicy)
{    
    KURL url = request.resourceRequest().url();

    ASSERT(m_frame->document());
    // FIXME: Should we move the isFeedWithNestedProtocolInHTTPFamily logic inside SecurityOrigin::canDisplay?
    if (!isFeedWithNestedProtocolInHTTPFamily(url) && !request.requester()->canDisplay(url)) {
        reportLocalLoadFailed(m_frame, url.string());
        return;
    }

    String referrer;
    String argsReferrer = request.resourceRequest().httpReferrer();
    if (!argsReferrer.isEmpty())
        referrer = argsReferrer;
    else
        referrer = m_outgoingReferrer;

    if (SecurityOrigin::shouldHideReferrer(url, referrer) || referrerPolicy == NoReferrer)
        referrer = String();
    
    FrameLoadType loadType;
    if (request.resourceRequest().cachePolicy() == ReloadIgnoringCacheData)
        loadType = FrameLoadTypeReload;
    else if (lockBackForwardList)
        loadType = FrameLoadTypeRedirectWithLockedBackForwardList;
    else
        loadType = FrameLoadTypeStandard;

    if (request.resourceRequest().httpMethod() == "POST")
        loadPostRequest(request.resourceRequest(), referrer, request.frameName(), lockHistory, loadType, event, formState.get());
    else
        loadURL(request.resourceRequest().url(), referrer, request.frameName(), lockHistory, loadType, event, formState.get());

    // FIXME: It's possible this targetFrame will not be the same frame that was targeted by the actual
    // load if frame names have changed.
    Frame* sourceFrame = formState ? formState->sourceFrame() : m_frame;
    Frame* targetFrame = sourceFrame->loader()->findFrameForNavigation(request.frameName());
    if (targetFrame && targetFrame != sourceFrame) {
        if (Page* page = targetFrame->page())
            page->chrome()->focus();
    }
}

void FrameLoader::loadURL(const KURL& newURL, const String& referrer, const String& frameName, bool lockHistory, FrameLoadType newLoadType,
    PassRefPtr<Event> event, PassRefPtr<FormState> prpFormState)
{
    if (m_inStopAllLoaders)
        return;

    RefPtr<FormState> formState = prpFormState;
    bool isFormSubmission = formState;
    
    ResourceRequest request(newURL);
    if (!referrer.isEmpty()) {
        request.setHTTPReferrer(referrer);
        RefPtr<SecurityOrigin> referrerOrigin = SecurityOrigin::createFromString(referrer);
        addHTTPOriginIfNeeded(request, referrerOrigin->toString());
    }
    addExtraFieldsToRequest(request, newLoadType, true, event || isFormSubmission);
    if (newLoadType == FrameLoadTypeReload || newLoadType == FrameLoadTypeReloadFromOrigin)
        request.setCachePolicy(ReloadIgnoringCacheData);

    ASSERT(newLoadType != FrameLoadTypeSame);

    // The search for a target frame is done earlier in the case of form submission.
    Frame* targetFrame = isFormSubmission ? 0 : findFrameForNavigation(frameName);
    if (targetFrame && targetFrame != m_frame) {
        targetFrame->loader()->loadURL(newURL, referrer, String(), lockHistory, newLoadType, event, formState.release());
        return;
    }

    if (m_pageDismissalEventBeingDispatched)
        return;

    NavigationAction action(newURL, newLoadType, isFormSubmission, event);

    if (!targetFrame && !frameName.isEmpty()) {
        policyChecker()->checkNewWindowPolicy(action, FrameLoader::callContinueLoadAfterNewWindowPolicy,
            request, formState.release(), frameName, this);
        return;
    }

    RefPtr<DocumentLoader> oldDocumentLoader = m_documentLoader;

    bool sameURL = shouldTreatURLAsSameAsCurrent(newURL);
    const String& httpMethod = request.httpMethod();
    
    // Make sure to do scroll to anchor processing even if the URL is
    // exactly the same so pages with '#' links and DHTML side effects
    // work properly.
    if (shouldScrollToAnchor(isFormSubmission, httpMethod, newLoadType, newURL)) {
        oldDocumentLoader->setTriggeringAction(action);
        policyChecker()->stopCheck();
        policyChecker()->setLoadType(newLoadType);
        policyChecker()->checkNavigationPolicy(request, oldDocumentLoader.get(), formState.release(),
            callContinueFragmentScrollAfterNavigationPolicy, this);
    } else {
        // must grab this now, since this load may stop the previous load and clear this flag
        bool isRedirect = m_quickRedirectComing;
        loadWithNavigationAction(request, action, lockHistory, newLoadType, formState.release());
        if (isRedirect) {
            m_quickRedirectComing = false;
            if (m_provisionalDocumentLoader)
                m_provisionalDocumentLoader->setIsClientRedirect(true);
        } else if (sameURL)
            // Example of this case are sites that reload the same URL with a different cookie
            // driving the generated content, or a master frame with links that drive a target
            // frame, where the user has clicked on the same link repeatedly.
            m_loadType = FrameLoadTypeSame;
    }
}

void FrameLoader::load(const ResourceRequest& request, bool lockHistory)
{
    load(request, SubstituteData(), lockHistory);
}

void FrameLoader::load(const ResourceRequest& request, const SubstituteData& substituteData, bool lockHistory)
{
    if (m_inStopAllLoaders)
        return;
        
    // FIXME: is this the right place to reset loadType? Perhaps this should be done after loading is finished or aborted.
    m_loadType = FrameLoadTypeStandard;
    RefPtr<DocumentLoader> loader = m_client->createDocumentLoader(request, substituteData);
    if (lockHistory && m_documentLoader)
        loader->setClientRedirectSourceForHistory(m_documentLoader->didCreateGlobalHistoryEntry() ? m_documentLoader->urlForHistory().string() : m_documentLoader->clientRedirectSourceForHistory());
    load(loader.get());
}

void FrameLoader::load(const ResourceRequest& request, const String& frameName, bool lockHistory)
{
    if (frameName.isEmpty()) {
        load(request, lockHistory);
        return;
    }

    Frame* frame = findFrameForNavigation(frameName);
    if (frame) {
        frame->loader()->load(request, lockHistory);
        return;
    }

    policyChecker()->checkNewWindowPolicy(NavigationAction(request.url(), NavigationTypeOther), FrameLoader::callContinueLoadAfterNewWindowPolicy, request, 0, frameName, this);
}

void FrameLoader::loadWithNavigationAction(const ResourceRequest& request, const NavigationAction& action, bool lockHistory, FrameLoadType type, PassRefPtr<FormState> formState)
{
    RefPtr<DocumentLoader> loader = m_client->createDocumentLoader(request, SubstituteData());
    if (lockHistory && m_documentLoader)
        loader->setClientRedirectSourceForHistory(m_documentLoader->didCreateGlobalHistoryEntry() ? m_documentLoader->urlForHistory().string() : m_documentLoader->clientRedirectSourceForHistory());

    loader->setTriggeringAction(action);
    if (m_documentLoader)
        loader->setOverrideEncoding(m_documentLoader->overrideEncoding());

    loadWithDocumentLoader(loader.get(), type, formState);
}

void FrameLoader::load(DocumentLoader* newDocumentLoader)
{
    ResourceRequest& r = newDocumentLoader->request();
    addExtraFieldsToMainResourceRequest(r);
    FrameLoadType type;

    if (shouldTreatURLAsSameAsCurrent(newDocumentLoader->originalRequest().url())) {
        r.setCachePolicy(ReloadIgnoringCacheData);
        type = FrameLoadTypeSame;
    } else
        type = FrameLoadTypeStandard;

    if (m_documentLoader)
        newDocumentLoader->setOverrideEncoding(m_documentLoader->overrideEncoding());
    
    // When we loading alternate content for an unreachable URL that we're
    // visiting in the history list, we treat it as a reload so the history list 
    // is appropriately maintained.
    //
    // FIXME: This seems like a dangerous overloading of the meaning of "FrameLoadTypeReload" ...
    // shouldn't a more explicit type of reload be defined, that means roughly 
    // "load without affecting history" ? 
    if (shouldReloadToHandleUnreachableURL(newDocumentLoader)) {
        // shouldReloadToHandleUnreachableURL() returns true only when the original load type is back-forward.
        // In this case we should save the document state now. Otherwise the state can be lost because load type is
        // changed and updateForBackForwardNavigation() will not be called when loading is committed.
        history()->saveDocumentAndScrollState();

        ASSERT(type == FrameLoadTypeStandard);
        type = FrameLoadTypeReload;
    }

    loadWithDocumentLoader(newDocumentLoader, type, 0);
}

void FrameLoader::loadWithDocumentLoader(DocumentLoader* loader, FrameLoadType type, PassRefPtr<FormState> prpFormState)
{
    // Retain because dispatchBeforeLoadEvent may release the last reference to it.
    RefPtr<Frame> protect(m_frame);

    ASSERT(m_client->hasWebView());

    // Unfortunately the view must be non-nil, this is ultimately due
    // to parser requiring a FrameView.  We should fix this dependency.

    ASSERT(m_frame->view());

    if (m_pageDismissalEventBeingDispatched)
        return;

    if (m_frame->document())
        m_previousUrl = m_frame->document()->url();

    policyChecker()->setLoadType(type);
    RefPtr<FormState> formState = prpFormState;
    bool isFormSubmission = formState;

    const KURL& newURL = loader->request().url();
    const String& httpMethod = loader->request().httpMethod();

    if (shouldScrollToAnchor(isFormSubmission,  httpMethod, policyChecker()->loadType(), newURL)) {
        RefPtr<DocumentLoader> oldDocumentLoader = m_documentLoader;
        NavigationAction action(newURL, policyChecker()->loadType(), isFormSubmission);

        oldDocumentLoader->setTriggeringAction(action);
        policyChecker()->stopCheck();
        policyChecker()->checkNavigationPolicy(loader->request(), oldDocumentLoader.get(), formState,
            callContinueFragmentScrollAfterNavigationPolicy, this);
    } else {
        if (Frame* parent = m_frame->tree()->parent())
            loader->setOverrideEncoding(parent->loader()->documentLoader()->overrideEncoding());

        policyChecker()->stopCheck();
        setPolicyDocumentLoader(loader);
        if (loader->triggeringAction().isEmpty())
            loader->setTriggeringAction(NavigationAction(newURL, policyChecker()->loadType(), isFormSubmission));

        if (Element* ownerElement = m_frame->ownerElement()) {
            if (!ownerElement->dispatchBeforeLoadEvent(loader->request().url().string())) {
                continueLoadAfterNavigationPolicy(loader->request(), formState, false);
                return;
            }
        }

        policyChecker()->checkNavigationPolicy(loader->request(), loader, formState,
            callContinueLoadAfterNavigationPolicy, this);
    }
}

void FrameLoader::reportLocalLoadFailed(Frame* frame, const String& url)
{
    ASSERT(!url.isEmpty());
    if (!frame)
        return;

    frame->domWindow()->console()->addMessage(JSMessageSource, LogMessageType, ErrorMessageLevel, "Not allowed to load local resource: " + url, 0, String());
}

const ResourceRequest& FrameLoader::initialRequest() const
{
    return activeDocumentLoader()->originalRequest();
}

bool FrameLoader::willLoadMediaElementURL(KURL& url)
{
    ResourceRequest request(url);

    unsigned long identifier;
    ResourceError error;
    requestFromDelegate(request, identifier, error);
    notifier()->sendRemainingDelegateMessages(m_documentLoader.get(), identifier, ResourceResponse(url, String(), -1, String(), String()), -1, -1, error);

    url = request.url();

    return error.isNull();
}

bool FrameLoader::shouldReloadToHandleUnreachableURL(DocumentLoader* docLoader)
{
    KURL unreachableURL = docLoader->unreachableURL();

    if (unreachableURL.isEmpty())
        return false;

    if (!isBackForwardLoadType(policyChecker()->loadType()))
        return false;

    // We only treat unreachableURLs specially during the delegate callbacks
    // for provisional load errors and navigation policy decisions. The former
    // case handles well-formed URLs that can't be loaded, and the latter
    // case handles malformed URLs and unknown schemes. Loading alternate content
    // at other times behaves like a standard load.
    DocumentLoader* compareDocumentLoader = 0;
    if (policyChecker()->delegateIsDecidingNavigationPolicy() || policyChecker()->delegateIsHandlingUnimplementablePolicy())
        compareDocumentLoader = m_policyDocumentLoader.get();
    else if (m_delegateIsHandlingProvisionalLoadError)
        compareDocumentLoader = m_provisionalDocumentLoader.get();

    return compareDocumentLoader && unreachableURL == compareDocumentLoader->request().url();
}

void FrameLoader::reloadWithOverrideEncoding(const String& encoding)
{
    if (!m_documentLoader)
        return;

    ResourceRequest request = m_documentLoader->request();
    KURL unreachableURL = m_documentLoader->unreachableURL();
    if (!unreachableURL.isEmpty())
        request.setURL(unreachableURL);

    request.setCachePolicy(ReturnCacheDataElseLoad);

    RefPtr<DocumentLoader> loader = m_client->createDocumentLoader(request, SubstituteData());
    setPolicyDocumentLoader(loader.get());

    loader->setOverrideEncoding(encoding);

    loadWithDocumentLoader(loader.get(), FrameLoadTypeReload, 0);
}

void FrameLoader::reload(bool endToEndReload)
{
    if (!m_documentLoader)
        return;

    // If a window is created by javascript, its main frame can have an empty but non-nil URL.
    // Reloading in this case will lose the current contents (see 4151001).
    if (m_documentLoader->request().url().isEmpty())
        return;

    ResourceRequest initialRequest = m_documentLoader->request();

    // Replace error-page URL with the URL we were trying to reach.
    KURL unreachableURL = m_documentLoader->unreachableURL();
    if (!unreachableURL.isEmpty())
        initialRequest.setURL(unreachableURL);
    
    // Create a new document loader for the reload, this will become m_documentLoader eventually,
    // but first it has to be the "policy" document loader, and then the "provisional" document loader.
    RefPtr<DocumentLoader> loader = m_client->createDocumentLoader(initialRequest, SubstituteData());

    ResourceRequest& request = loader->request();

    // FIXME: We don't have a mechanism to revalidate the main resource without reloading at the moment.
    request.setCachePolicy(ReloadIgnoringCacheData);

    // If we're about to re-post, set up action so the application can warn the user.
    if (request.httpMethod() == "POST")
        loader->setTriggeringAction(NavigationAction(request.url(), NavigationTypeFormResubmitted));

    loader->setOverrideEncoding(m_documentLoader->overrideEncoding());
    
    loadWithDocumentLoader(loader.get(), endToEndReload ? FrameLoadTypeReloadFromOrigin : FrameLoadTypeReload, 0);
}

static bool canAccessAncestor(const SecurityOrigin* activeSecurityOrigin, Frame* targetFrame)
{
    // targetFrame can be NULL when we're trying to navigate a top-level frame
    // that has a NULL opener.
    if (!targetFrame)
        return false;

    const bool isLocalActiveOrigin = activeSecurityOrigin->isLocal();
    for (Frame* ancestorFrame = targetFrame; ancestorFrame; ancestorFrame = ancestorFrame->tree()->parent()) {
        Document* ancestorDocument = ancestorFrame->document();
        if (!ancestorDocument)
            return true;

        const SecurityOrigin* ancestorSecurityOrigin = ancestorDocument->securityOrigin();
        if (activeSecurityOrigin->canAccess(ancestorSecurityOrigin))
            return true;
        
        // Allow file URL descendant navigation even when allowFileAccessFromFileURLs is false.
        if (isLocalActiveOrigin && ancestorSecurityOrigin->isLocal())
            return true;
    }

    return false;
}

bool FrameLoader::shouldAllowNavigation(Frame* targetFrame) const
{
    // The navigation change is safe if the active frame is:
    //   - in the same security origin as the target or one of the target's
    //     ancestors.
    //
    // Or the target frame is:
    //   - a top-level frame in the frame hierarchy and the active frame can
    //     navigate the target frame's opener per above or it is the opener of
    //     the target frame.

    if (!targetFrame)
        return true;

    // Performance optimization.
    if (m_frame == targetFrame)
        return true;

    // Let a frame navigate the top-level window that contains it.  This is
    // important to allow because it lets a site "frame-bust" (escape from a
    // frame created by another web site).
    if (!isDocumentSandboxed(m_frame, SandboxTopNavigation) && targetFrame == m_frame->tree()->top())
        return true;

    // A sandboxed frame can only navigate itself and its descendants.
    if (isDocumentSandboxed(m_frame, SandboxNavigation) && !targetFrame->tree()->isDescendantOf(m_frame))
        return false;

    // Let a frame navigate its opener if the opener is a top-level window.
    if (!targetFrame->tree()->parent() && m_frame->loader()->opener() == targetFrame)
        return true;

    Document* activeDocument = m_frame->document();
    ASSERT(activeDocument);
    const SecurityOrigin* activeSecurityOrigin = activeDocument->securityOrigin();

    // For top-level windows, check the opener.
    if (!targetFrame->tree()->parent() && canAccessAncestor(activeSecurityOrigin, targetFrame->loader()->opener()))
        return true;

    // In general, check the frame's ancestors.
    if (canAccessAncestor(activeSecurityOrigin, targetFrame))
        return true;

    Settings* settings = targetFrame->settings();
    if (settings && !settings->privateBrowsingEnabled()) {
        Document* targetDocument = targetFrame->document();
        // FIXME: this error message should contain more specifics of why the navigation change is not allowed.
        String message = "Unsafe JavaScript attempt to initiate a navigation change for frame with URL " +
                         targetDocument->url().string() + " from frame with URL " + activeDocument->url().string() + ".\n";

        // FIXME: should we print to the console of the activeFrame as well?
        targetFrame->domWindow()->console()->addMessage(JSMessageSource, LogMessageType, ErrorMessageLevel, message, 1, String());
    }
    
    return false;
}

void FrameLoader::stopAllLoaders(ClearProvisionalItemPolicy clearProvisionalItemPolicy)
{
    ASSERT(!m_frame->document() || !m_frame->document()->inPageCache());
    if (m_pageDismissalEventBeingDispatched)
        return;

    // If this method is called from within this method, infinite recursion can occur (3442218). Avoid this.
    if (m_inStopAllLoaders)
        return;

    m_inStopAllLoaders = true;

    policyChecker()->stopCheck();

    // If no new load is in progress, we should clear the provisional item from history
    // before we call stopLoading.
    if (clearProvisionalItemPolicy == ShouldClearProvisionalItem)
        history()->setProvisionalItem(0);

    for (RefPtr<Frame> child = m_frame->tree()->firstChild(); child; child = child->tree()->nextSibling())
        child->loader()->stopAllLoaders(clearProvisionalItemPolicy);
    if (m_provisionalDocumentLoader)
        m_provisionalDocumentLoader->stopLoading();
    if (m_documentLoader)
        m_documentLoader->stopLoading();

    setProvisionalDocumentLoader(0);
    
#if ENABLE(WEB_ARCHIVE) || ENABLE(MHTML)
    if (m_documentLoader)
        m_documentLoader->clearArchiveResources();
#endif

    m_checkTimer.stop();

    m_inStopAllLoaders = false;    
}

void FrameLoader::stopForUserCancel(bool deferCheckLoadComplete)
{
    stopAllLoaders();
    
    if (deferCheckLoadComplete)
        scheduleCheckLoadComplete();
    else if (m_frame->page())
        checkLoadComplete();
}

DocumentLoader* FrameLoader::activeDocumentLoader() const
{
    if (m_state == FrameStateProvisional)
        return m_provisionalDocumentLoader.get();
    return m_documentLoader.get();
}

bool FrameLoader::isLoading() const
{
    DocumentLoader* docLoader = activeDocumentLoader();
    if (!docLoader)
        return false;
    return docLoader->isLoadingMainResource() || docLoader->isLoadingSubresources() || docLoader->isLoadingPlugIns();
}

bool FrameLoader::frameHasLoaded() const
{
    return m_stateMachine.committedFirstRealDocumentLoad() || (m_provisionalDocumentLoader && !m_stateMachine.creatingInitialEmptyDocument()); 
}

void FrameLoader::transferLoadingResourcesFromPage(Page* oldPage)
{
    ASSERT(oldPage != m_frame->page());
    if (isLoading()) {
        activeDocumentLoader()->transferLoadingResourcesFromPage(oldPage);
        oldPage->progress()->progressCompleted(m_frame);
        if (m_frame->page())
            m_frame->page()->progress()->progressStarted(m_frame);
    }
}

void FrameLoader::dispatchTransferLoadingResourceFromPage(unsigned long identifier, DocumentLoader* docLoader, const ResourceRequest& request, Page* oldPage)
{
    notifier()->dispatchTransferLoadingResourceFromPage(identifier, docLoader, request, oldPage);
}

void FrameLoader::setDocumentLoader(DocumentLoader* loader)
{
    if (!loader && !m_documentLoader)
        return;
    
    ASSERT(loader != m_documentLoader);
    ASSERT(!loader || loader->frameLoader() == this);

    m_client->prepareForDataSourceReplacement();
    detachChildren();
    if (m_documentLoader)
        m_documentLoader->detachFromFrame();

    m_documentLoader = loader;
}

void FrameLoader::setPolicyDocumentLoader(DocumentLoader* loader)
{
    if (m_policyDocumentLoader == loader)
        return;

    ASSERT(m_frame);
    if (loader)
        loader->setFrame(m_frame);
    if (m_policyDocumentLoader
            && m_policyDocumentLoader != m_provisionalDocumentLoader
            && m_policyDocumentLoader != m_documentLoader)
        m_policyDocumentLoader->detachFromFrame();

    m_policyDocumentLoader = loader;
}

void FrameLoader::setProvisionalDocumentLoader(DocumentLoader* loader)
{
    ASSERT(!loader || !m_provisionalDocumentLoader);
    ASSERT(!loader || loader->frameLoader() == this);

    if (m_provisionalDocumentLoader && m_provisionalDocumentLoader != m_documentLoader)
        m_provisionalDocumentLoader->detachFromFrame();

    m_provisionalDocumentLoader = loader;
}

double FrameLoader::timeOfLastCompletedLoad()
{
    return storedTimeOfLastCompletedLoad;
}

void FrameLoader::setState(FrameState newState)
{    
    m_state = newState;
    
    if (newState == FrameStateProvisional)
        provisionalLoadStarted();
    else if (newState == FrameStateComplete) {
        frameLoadCompleted();
        storedTimeOfLastCompletedLoad = currentTime();
        if (m_documentLoader)
            m_documentLoader->stopRecordingResponses();
    }
}

void FrameLoader::clearProvisionalLoad()
{
    setProvisionalDocumentLoader(0);
    if (Page* page = m_frame->page())
        page->progress()->progressCompleted(m_frame);
    setState(FrameStateComplete);
}

void FrameLoader::commitProvisionalLoad()
{
    RefPtr<CachedPage> cachedPage = m_loadingFromCachedPage ? pageCache()->get(history()->provisionalItem()) : 0;
    RefPtr<DocumentLoader> pdl = m_provisionalDocumentLoader;

    LOG(PageCache, "WebCoreLoading %s: About to commit provisional load from previous URL '%s' to new URL '%s'", m_frame->tree()->uniqueName().string().utf8().data(),
        m_frame->document() ? m_frame->document()->url().string().utf8().data() : "", 
        pdl ? pdl->url().string().utf8().data() : "<no provisional DocumentLoader>");

    // Check to see if we need to cache the page we are navigating away from into the back/forward cache.
    // We are doing this here because we know for sure that a new page is about to be loaded.
    HistoryItem* item = history()->currentItem();
    if (!m_frame->tree()->parent() && PageCache::canCache(m_frame->page()) && !item->isInPageCache())
        pageCache()->add(item, m_frame->page());

    if (m_loadType != FrameLoadTypeReplace)
        closeOldDataSources();

    if (!cachedPage && !m_stateMachine.creatingInitialEmptyDocument())
        m_client->makeRepresentation(pdl.get());

    transitionToCommitted(cachedPage);

    if (pdl) {
        // Check if the destination page is allowed to access the previous page's timing information.
        RefPtr<SecurityOrigin> securityOrigin = SecurityOrigin::create(pdl->request().url());
        m_documentLoader->timing()->hasSameOriginAsPreviousDocument = securityOrigin->canRequest(m_previousUrl);
    }

    // Call clientRedirectCancelledOrFinished() here so that the frame load delegate is notified that the redirect's
    // status has changed, if there was a redirect.  The frame load delegate may have saved some state about
    // the redirect in its -webView:willPerformClientRedirectToURL:delay:fireDate:forFrame:.  Since we are
    // just about to commit a new page, there cannot possibly be a pending redirect at this point.
    if (m_sentRedirectNotification)
        clientRedirectCancelledOrFinished(false);
    
    if (cachedPage && cachedPage->document()) {
        prepareForCachedPageRestore();
        cachedPage->restore(m_frame->page());

        dispatchDidCommitLoad();

        // If we have a title let the WebView know about it. 
        StringWithDirection title = m_documentLoader->title();
        if (!title.isNull())
            m_client->dispatchDidReceiveTitle(title);

        checkCompleted();
    } else
        didOpenURL();

    LOG(Loading, "WebCoreLoading %s: Finished committing provisional load to URL %s", m_frame->tree()->uniqueName().string().utf8().data(),
        m_frame->document() ? m_frame->document()->url().string().utf8().data() : "");

    if (m_loadType == FrameLoadTypeStandard && m_documentLoader->isClientRedirect())
        history()->updateForClientRedirect();

    if (m_loadingFromCachedPage) {
        m_frame->document()->documentDidBecomeActive();
        
        // Force a layout to update view size and thereby update scrollbars.
        m_frame->view()->forceLayout();

        const ResponseVector& responses = m_documentLoader->responses();
        size_t count = responses.size();
        for (size_t i = 0; i < count; i++) {
            const ResourceResponse& response = responses[i];
            // FIXME: If the WebKit client changes or cancels the request, this is not respected.
            ResourceError error;
            unsigned long identifier;
            ResourceRequest request(response.url());
            requestFromDelegate(request, identifier, error);
            // FIXME: If we get a resource with more than 2B bytes, this code won't do the right thing.
            // However, with today's computers and networking speeds, this won't happen in practice.
            // Could be an issue with a giant local file.
            notifier()->sendRemainingDelegateMessages(m_documentLoader.get(), identifier, response, static_cast<int>(response.expectedContentLength()), 0, error);
        }
        
        pageCache()->remove(history()->currentItem());

        m_documentLoader->setPrimaryLoadComplete(true);

        // FIXME: Why only this frame and not parent frames?
        checkLoadCompleteForThisFrame();
    }
}

void FrameLoader::transitionToCommitted(PassRefPtr<CachedPage> cachedPage)
{
    ASSERT(m_client->hasWebView());
    ASSERT(m_state == FrameStateProvisional);

    if (m_state != FrameStateProvisional)
        return;

    if (m_frame->view())
        m_frame->view()->scrollAnimator()->cancelAnimations();

    m_client->setCopiesOnScroll();
    history()->updateForCommit();

    // The call to closeURL() invokes the unload event handler, which can execute arbitrary
    // JavaScript. If the script initiates a new load, we need to abandon the current load,
    // or the two will stomp each other.
    DocumentLoader* pdl = m_provisionalDocumentLoader.get();
    if (m_documentLoader)
        closeURL();
    if (pdl != m_provisionalDocumentLoader)
        return;

    // Nothing else can interupt this commit - set the Provisional->Committed transition in stone
    if (m_documentLoader)
        m_documentLoader->stopLoadingSubresources();
    if (m_documentLoader)
        m_documentLoader->stopLoadingPlugIns();

    setDocumentLoader(m_provisionalDocumentLoader.get());
    setProvisionalDocumentLoader(0);
    setState(FrameStateCommittedPage);

#if ENABLE(TOUCH_EVENTS)
    if (isLoadingMainFrame())
        m_frame->page()->chrome()->client()->needTouchEvents(false);
#endif

    // Handle adding the URL to the back/forward list.
    DocumentLoader* dl = m_documentLoader.get();

    switch (m_loadType) {
        case FrameLoadTypeForward:
        case FrameLoadTypeBack:
        case FrameLoadTypeIndexedBackForward:
            if (m_frame->page()) {
                // If the first load within a frame is a navigation within a back/forward list that was attached
                // without any of the items being loaded then we need to update the history in a similar manner as
                // for a standard load with the exception of updating the back/forward list (<rdar://problem/8091103>).
                if (!m_stateMachine.committedFirstRealDocumentLoad() && isLoadingMainFrame())
                    history()->updateForStandardLoad(HistoryController::UpdateAllExceptBackForwardList);

                history()->updateForBackForwardNavigation();

                // For cached pages, CachedFrame::restore will take care of firing the popstate event with the history item's state object
                if (history()->currentItem() && !cachedPage)
                    m_pendingStateObject = history()->currentItem()->stateObject();

                // Create a document view for this document, or used the cached view.
                if (cachedPage) {
                    DocumentLoader* cachedDocumentLoader = cachedPage->documentLoader();
                    ASSERT(cachedDocumentLoader);
                    cachedDocumentLoader->setFrame(m_frame);
                    m_client->transitionToCommittedFromCachedFrame(cachedPage->cachedMainFrame());

                } else
                    m_client->transitionToCommittedForNewPage();
            }
            break;

        case FrameLoadTypeReload:
        case FrameLoadTypeReloadFromOrigin:
        case FrameLoadTypeSame:
        case FrameLoadTypeReplace:
            history()->updateForReload();
            m_client->transitionToCommittedForNewPage();
            break;

        case FrameLoadTypeStandard:
            history()->updateForStandardLoad();
            if (m_frame->view())
                m_frame->view()->setScrollbarsSuppressed(true);
            m_client->transitionToCommittedForNewPage();
            break;

        case FrameLoadTypeRedirectWithLockedBackForwardList:
            history()->updateForRedirectWithLockedBackForwardList();
            m_client->transitionToCommittedForNewPage();
            break;

        // FIXME Remove this check when dummy ds is removed (whatever "dummy ds" is).
        // An exception should be thrown if we're in the FrameLoadTypeUninitialized state.
        default:
            ASSERT_NOT_REACHED();
    }

    m_documentLoader->writer()->setMIMEType(dl->responseMIMEType());

    // Tell the client we've committed this URL.
    ASSERT(m_frame->view());

    if (m_stateMachine.creatingInitialEmptyDocument())
        return;

    if (!m_stateMachine.committedFirstRealDocumentLoad())
        m_stateMachine.advanceTo(FrameLoaderStateMachine::DisplayingInitialEmptyDocumentPostCommit);

    if (!m_client->hasHTMLView())
        receivedFirstData();
}

void FrameLoader::clientRedirectCancelledOrFinished(bool cancelWithLoadInProgress)
{
    // Note that -webView:didCancelClientRedirectForFrame: is called on the frame load delegate even if
    // the redirect succeeded.  We should either rename this API, or add a new method, like
    // -webView:didFinishClientRedirectForFrame:
    m_client->dispatchDidCancelClientRedirect();

    if (!cancelWithLoadInProgress)
        m_quickRedirectComing = false;

    m_sentRedirectNotification = false;
}

void FrameLoader::clientRedirected(const KURL& url, double seconds, double fireDate, bool lockBackForwardList)
{
    m_client->dispatchWillPerformClientRedirect(url, seconds, fireDate);
    
    // Remember that we sent a redirect notification to the frame load delegate so that when we commit
    // the next provisional load, we can send a corresponding -webView:didCancelClientRedirectForFrame:
    m_sentRedirectNotification = true;
    
    // If a "quick" redirect comes in, we set a special mode so we treat the next
    // load as part of the original navigation. If we don't have a document loader, we have
    // no "original" load on which to base a redirect, so we treat the redirect as a normal load.
    // Loads triggered by JavaScript form submissions never count as quick redirects.
    m_quickRedirectComing = (lockBackForwardList || history()->currentItemShouldBeReplaced()) && m_documentLoader && !m_isExecutingJavaScriptFormAction;
}

bool FrameLoader::shouldReload(const KURL& currentURL, const KURL& destinationURL)
{
    // This function implements the rule: "Don't reload if navigating by fragment within
    // the same URL, but do reload if going to a new URL or to the same URL with no
    // fragment identifier at all."
    if (!destinationURL.hasFragmentIdentifier())
        return true;
    return !equalIgnoringFragmentIdentifier(currentURL, destinationURL);
}

void FrameLoader::closeOldDataSources()
{
    // FIXME: Is it important for this traversal to be postorder instead of preorder?
    // If so, add helpers for postorder traversal, and use them. If not, then lets not
    // use a recursive algorithm here.
    for (Frame* child = m_frame->tree()->firstChild(); child; child = child->tree()->nextSibling())
        child->loader()->closeOldDataSources();
    
    if (m_documentLoader)
        m_client->dispatchWillClose();

    m_client->setMainFrameDocumentReady(false); // stop giving out the actual DOMDocument to observers
}

void FrameLoader::prepareForCachedPageRestore()
{
    ASSERT(!m_frame->tree()->parent());
    ASSERT(m_frame->page());
    ASSERT(m_frame->page()->mainFrame() == m_frame);

    m_frame->navigationScheduler()->cancel();

    // We still have to close the previous part page.
    closeURL();
    
    // Delete old status bar messages (if it _was_ activated on last URL).
    if (m_frame->script()->canExecuteScripts(NotAboutToExecuteScript)) {
        if (DOMWindow* window = m_frame->existingDOMWindow()) {
            window->setStatus(String());
            window->setDefaultStatus(String());
        }
    }
}

void FrameLoader::open(CachedFrameBase& cachedFrame)
{
    m_isComplete = false;
    
    // Don't re-emit the load event.
    m_didCallImplicitClose = true;

    KURL url = cachedFrame.url();

    // FIXME: I suspect this block of code doesn't do anything.
    if (url.protocolInHTTPFamily() && !url.host().isEmpty() && url.path().isEmpty())
        url.setPath("/");

    m_hasReceivedFirstData = false;

    started();
    clear(true, true, cachedFrame.isMainFrame());

    Document* document = cachedFrame.document();
    ASSERT(document);
    document->setInPageCache(false);

    m_needsClear = true;
    m_isComplete = false;
    m_didCallImplicitClose = false;
    m_outgoingReferrer = url.string();

    FrameView* view = cachedFrame.view();
    
    // When navigating to a CachedFrame its FrameView should never be null.  If it is we'll crash in creative ways downstream.
    ASSERT(view);
    view->setWasScrolledByUser(false);

    // Use the current ScrollView's frame rect.
    if (m_frame->view()) {
        IntRect rect = m_frame->view()->frameRect();
        view->setFrameRect(rect);
        view->setBoundsSize(rect.size());
    }
    m_frame->setView(view);
    
    m_frame->setDocument(document);
    m_frame->setDOMWindow(cachedFrame.domWindow());
    m_frame->domWindow()->setURL(document->url());
    m_frame->domWindow()->setSecurityOrigin(document->securityOrigin());

    updateFirstPartyForCookies();

    cachedFrame.restore();
}

void FrameLoader::finishedLoading()
{
    // Retain because the stop may release the last reference to it.
    RefPtr<Frame> protect(m_frame);

    RefPtr<DocumentLoader> dl = activeDocumentLoader();
    dl->finishedLoading();
    if (!dl->mainDocumentError().isNull() || !dl->frameLoader())
        return;
    dl->setPrimaryLoadComplete(true);
    m_client->dispatchDidLoadMainResource(dl.get());
    checkLoadComplete();
}

bool FrameLoader::isHostedByObjectElement() const
{
    HTMLFrameOwnerElement* owner = m_frame->ownerElement();
    return owner && owner->hasTagName(objectTag);
}

bool FrameLoader::isLoadingMainFrame() const
{
    Page* page = m_frame->page();
    return page && m_frame == page->mainFrame();
}

void FrameLoader::finishedLoadingDocument(DocumentLoader* loader)
{
    if (m_stateMachine.creatingInitialEmptyDocument())
        return;

#if !ENABLE(WEB_ARCHIVE) && !ENABLE(MHTML)
    m_client->finishedLoading(loader);
#else
    // Give archive machinery a crack at this document. If the MIME type is not an archive type, it will return 0.
    m_archive = ArchiveFactory::create(loader->response().url(), loader->mainResourceData().get(), loader->responseMIMEType());
    if (!m_archive) {
        m_client->finishedLoading(loader);
        return;
    }

    // FIXME: The remainder of this function should be moved to DocumentLoader.

    loader->addAllArchiveResources(m_archive.get());

    ArchiveResource* mainResource = m_archive->mainResource();
    loader->setParsedArchiveData(mainResource->data());

    loader->writer()->setMIMEType(mainResource->mimeType());

    closeURL();
    didOpenURL();

    ASSERT(m_frame->document());
    String userChosenEncoding = documentLoader()->overrideEncoding();
    bool encodingIsUserChosen = !userChosenEncoding.isNull();
    loader->writer()->setEncoding(encodingIsUserChosen ? userChosenEncoding : mainResource->textEncoding(), encodingIsUserChosen);
    loader->writer()->addData(mainResource->data()->data(), mainResource->data()->size());
#endif // ENABLE(WEB_ARCHIVE)
}

bool FrameLoader::isReplacing() const
{
    return m_loadType == FrameLoadTypeReplace;
}

void FrameLoader::setReplacing()
{
    m_loadType = FrameLoadTypeReplace;
}

bool FrameLoader::subframeIsLoading() const
{
    // It's most likely that the last added frame is the last to load so we walk backwards.
    for (Frame* child = m_frame->tree()->lastChild(); child; child = child->tree()->previousSibling()) {
        FrameLoader* childLoader = child->loader();
        DocumentLoader* documentLoader = childLoader->documentLoader();
        if (documentLoader && documentLoader->isLoadingInAPISense())
            return true;
        documentLoader = childLoader->provisionalDocumentLoader();
        if (documentLoader && documentLoader->isLoadingInAPISense())
            return true;
        documentLoader = childLoader->policyDocumentLoader();
        if (documentLoader)
            return true;
    }
    return false;
}

void FrameLoader::willChangeTitle(DocumentLoader* loader)
{
    m_client->willChangeTitle(loader);
}

FrameLoadType FrameLoader::loadType() const
{
    return m_loadType;
}
    
CachePolicy FrameLoader::subresourceCachePolicy() const
{
    if (m_isComplete)
        return CachePolicyVerify;

    if (m_loadType == FrameLoadTypeReloadFromOrigin)
        return CachePolicyReload;

    if (Frame* parentFrame = m_frame->tree()->parent()) {
        CachePolicy parentCachePolicy = parentFrame->loader()->subresourceCachePolicy();
        if (parentCachePolicy != CachePolicyVerify)
            return parentCachePolicy;
    }
    
    if (m_loadType == FrameLoadTypeReload)
        return CachePolicyRevalidate;

    const ResourceRequest& request(documentLoader()->request());
#if PLATFORM(MAC)
    if (request.cachePolicy() == ReloadIgnoringCacheData && !equalIgnoringCase(request.httpMethod(), "post") && ResourceRequest::useQuickLookResourceCachingQuirks())
        return CachePolicyRevalidate;
#endif

    if (request.cachePolicy() == ReturnCacheDataElseLoad)
        return CachePolicyHistoryBuffer;

    return CachePolicyVerify;
}

void FrameLoader::checkLoadCompleteForThisFrame()
{
    ASSERT(m_client->hasWebView());

    switch (m_state) {
        case FrameStateProvisional: {
            if (m_delegateIsHandlingProvisionalLoadError)
                return;

            RefPtr<DocumentLoader> pdl = m_provisionalDocumentLoader;
            if (!pdl)
                return;
                
            // If we've received any errors we may be stuck in the provisional state and actually complete.
            const ResourceError& error = pdl->mainDocumentError();
            if (error.isNull())
                return;

            // Check all children first.
            RefPtr<HistoryItem> item;
            if (Page* page = m_frame->page())
                if (isBackForwardLoadType(loadType()))
                    // Reset the back forward list to the last committed history item at the top level.
                    item = page->mainFrame()->loader()->history()->currentItem();
                
            // Only reset if we aren't already going to a new provisional item.
            bool shouldReset = !history()->provisionalItem();
            if (!pdl->isLoadingInAPISense() || pdl->isStopping()) {
                m_delegateIsHandlingProvisionalLoadError = true;
                m_client->dispatchDidFailProvisionalLoad(error);
                m_delegateIsHandlingProvisionalLoadError = false;

                ASSERT(!pdl->isLoading());
                ASSERT(!pdl->isLoadingMainResource());
                ASSERT(!pdl->isLoadingSubresources());
                ASSERT(!pdl->isLoadingPlugIns());

                // If we're in the middle of loading multipart data, we need to restore the document loader.
                if (isReplacing() && !m_documentLoader.get())
                    setDocumentLoader(m_provisionalDocumentLoader.get());

                // Finish resetting the load state, but only if another load hasn't been started by the
                // delegate callback.
                if (pdl == m_provisionalDocumentLoader)
                    clearProvisionalLoad();
                else if (activeDocumentLoader()) {
                    KURL unreachableURL = activeDocumentLoader()->unreachableURL();
                    if (!unreachableURL.isEmpty() && unreachableURL == pdl->request().url())
                        shouldReset = false;
                }
            }
            if (shouldReset && item)
                if (Page* page = m_frame->page()) {
                    page->backForward()->setCurrentItem(item.get());
                    m_frame->loader()->client()->updateGlobalHistoryItemForPage();
                }
            return;
        }
        
        case FrameStateCommittedPage: {
            DocumentLoader* dl = m_documentLoader.get();            
            if (!dl || (dl->isLoadingInAPISense() && !dl->isStopping()))
                return;

            setState(FrameStateComplete);

            // FIXME: Is this subsequent work important if we already navigated away?
            // Maybe there are bugs because of that, or extra work we can skip because
            // the new page is ready.

            m_client->forceLayoutForNonHTML();
             
            // If the user had a scroll point, scroll to it, overriding the anchor point if any.
            if (m_frame->page()) {
                if (isBackForwardLoadType(m_loadType) || m_loadType == FrameLoadTypeReload || m_loadType == FrameLoadTypeReloadFromOrigin)
                    history()->restoreScrollPositionAndViewState();
            }

            if (m_stateMachine.creatingInitialEmptyDocument() || !m_stateMachine.committedFirstRealDocumentLoad())
                return;

            const ResourceError& error = dl->mainDocumentError();
            if (!error.isNull())
                m_client->dispatchDidFailLoad(error);
            else
                m_client->dispatchDidFinishLoad();

            if (Page* page = m_frame->page())
                page->progress()->progressCompleted(m_frame);
            return;
        }
        
        case FrameStateComplete:
            frameLoadCompleted();
            return;
    }

    ASSERT_NOT_REACHED();
}

void FrameLoader::continueLoadAfterWillSubmitForm()
{
    if (!m_provisionalDocumentLoader)
        return;

    // DocumentLoader calls back to our prepareForLoadStart
    m_provisionalDocumentLoader->prepareForLoadStart();
    
    // The load might be cancelled inside of prepareForLoadStart(), nulling out the m_provisionalDocumentLoader, 
    // so we need to null check it again.
    if (!m_provisionalDocumentLoader)
        return;

    DocumentLoader* activeDocLoader = activeDocumentLoader();
    if (activeDocLoader && activeDocLoader->isLoadingMainResource())
        return;

    m_loadingFromCachedPage = false;

    unsigned long identifier = 0;

    if (Page* page = m_frame->page()) {
        identifier = page->progress()->createUniqueIdentifier();
        notifier()->assignIdentifierToInitialRequest(identifier, m_provisionalDocumentLoader.get(), m_provisionalDocumentLoader->originalRequest());
    }

    ASSERT(!m_provisionalDocumentLoader->timing()->navigationStart);
    m_provisionalDocumentLoader->timing()->navigationStart = currentTime();

    if (!m_provisionalDocumentLoader->startLoadingMainResource(identifier))
        m_provisionalDocumentLoader->updateLoading();
}

void FrameLoader::didFirstLayout()
{
    if (m_frame->page() && isBackForwardLoadType(m_loadType))
        history()->restoreScrollPositionAndViewState();

    if (m_stateMachine.committedFirstRealDocumentLoad() && !m_stateMachine.isDisplayingInitialEmptyDocument() && !m_stateMachine.firstLayoutDone())
        m_stateMachine.advanceTo(FrameLoaderStateMachine::FirstLayoutDone);

    m_client->dispatchDidFirstLayout();
}

void FrameLoader::didFirstVisuallyNonEmptyLayout()
{
    m_client->dispatchDidFirstVisuallyNonEmptyLayout();
}

void FrameLoader::frameLoadCompleted()
{
    // Note: Can be called multiple times.

    m_client->frameLoadCompleted();

    history()->updateForFrameLoadCompleted();

    // After a canceled provisional load, firstLayoutDone is false.
    // Reset it to true if we're displaying a page.
    if (m_documentLoader && m_stateMachine.committedFirstRealDocumentLoad() && !m_stateMachine.isDisplayingInitialEmptyDocument() && !m_stateMachine.firstLayoutDone())
        m_stateMachine.advanceTo(FrameLoaderStateMachine::FirstLayoutDone);
}

void FrameLoader::detachChildren()
{
    // FIXME: Is it really necessary to do this in reverse order?
    Frame* previous;
    for (Frame* child = m_frame->tree()->lastChild(); child; child = previous) {
        previous = child->tree()->previousSibling();
        child->loader()->detachFromParent();
    }
}

void FrameLoader::closeAndRemoveChild(Frame* child)
{
    child->tree()->detachFromParent();

    child->setView(0);
    if (child->ownerElement() && child->page())
        child->page()->decrementFrameCount();
    // FIXME: The page isn't being destroyed, so it's not right to call a function named pageDestroyed().
    child->pageDestroyed();

    m_frame->tree()->removeChild(child);
}

// Called every time a resource is completely loaded or an error is received.
void FrameLoader::checkLoadComplete()
{
    ASSERT(m_client->hasWebView());
    
    m_shouldCallCheckLoadComplete = false;

    // FIXME: Always traversing the entire frame tree is a bit inefficient, but 
    // is currently needed in order to null out the previous history item for all frames.
    if (Page* page = m_frame->page()) {
        Vector<RefPtr<Frame>, 10> frames;
        for (RefPtr<Frame> frame = page->mainFrame(); frame; frame = frame->tree()->traverseNext())
            frames.append(frame);
        // To process children before their parents, iterate the vector backwards.
        for (size_t i = frames.size(); i; --i)
            frames[i - 1]->loader()->checkLoadCompleteForThisFrame();
    }
}

int FrameLoader::numPendingOrLoadingRequests(bool recurse) const
{
    if (!recurse)
        return m_frame->document()->cachedResourceLoader()->requestCount();

    int count = 0;
    for (Frame* frame = m_frame; frame; frame = frame->tree()->traverseNext(m_frame))
        count += frame->document()->cachedResourceLoader()->requestCount();
    return count;
}

String FrameLoader::userAgent(const KURL& url) const
{
    String userAgent = m_client->userAgent(url);
    InspectorInstrumentation::applyUserAgentOverride(m_frame, &userAgent);
    return userAgent;
}

void FrameLoader::handledOnloadEvents()
{
    m_client->dispatchDidHandleOnloadEvents();

    if (documentLoader())
        documentLoader()->handledOnloadEvents();
}

void FrameLoader::frameDetached()
{
    stopAllLoaders();
    m_frame->document()->stopActiveDOMObjects();
    detachFromParent();
}

void FrameLoader::detachFromParent()
{
    RefPtr<Frame> protect(m_frame);

    closeURL();
    history()->saveScrollPositionAndViewStateToItem(history()->currentItem());
    detachChildren();
    // stopAllLoaders() needs to be called after detachChildren(), because detachedChildren()
    // will trigger the unload event handlers of any child frames, and those event
    // handlers might start a new subresource load in this frame.
    stopAllLoaders();

    InspectorInstrumentation::frameDetachedFromParent(m_frame);

    detachViewsAndDocumentLoader();

    if (Frame* parent = m_frame->tree()->parent()) {
        parent->loader()->closeAndRemoveChild(m_frame);
        parent->loader()->scheduleCheckCompleted();
    } else {
        m_frame->setView(0);
        // FIXME: The page isn't being destroyed, so it's not right to call a function named pageDestroyed().
        m_frame->pageDestroyed();
    }
}

void FrameLoader::detachViewsAndDocumentLoader()
{
    m_client->detachedFromParent2();
    setDocumentLoader(0);
    m_client->detachedFromParent3();
}
    
void FrameLoader::addExtraFieldsToSubresourceRequest(ResourceRequest& request)
{
    addExtraFieldsToRequest(request, m_loadType, false, false);
}

void FrameLoader::addExtraFieldsToMainResourceRequest(ResourceRequest& request)
{
    addExtraFieldsToRequest(request, m_loadType, true, false);
}

void FrameLoader::addExtraFieldsToRequest(ResourceRequest& request, FrameLoadType loadType, bool mainResource, bool cookiePolicyURLFromRequest)
{
    // Don't set the cookie policy URL if it's already been set.
    // But make sure to set it on all requests, as it has significance beyond the cookie policy for all protocols (<rdar://problem/6616664>).
    if (request.firstPartyForCookies().isEmpty()) {
        if (mainResource && (isLoadingMainFrame() || cookiePolicyURLFromRequest))
            request.setFirstPartyForCookies(request.url());
        else if (Document* document = m_frame->document())
            request.setFirstPartyForCookies(document->firstPartyForCookies());
    }

    // The remaining modifications are only necessary for HTTP and HTTPS.
    if (!request.url().isEmpty() && !request.url().protocolInHTTPFamily())
        return;

    applyUserAgent(request);
    
    // If we inherit cache policy from a main resource, we use the DocumentLoader's 
    // original request cache policy for two reasons:
    // 1. For POST requests, we mutate the cache policy for the main resource,
    //    but we do not want this to apply to subresources
    // 2. Delegates that modify the cache policy using willSendRequest: should
    //    not affect any other resources. Such changes need to be done
    //    per request.
    if (!mainResource) {
        if (request.isConditional())
            request.setCachePolicy(ReloadIgnoringCacheData);
        else if (documentLoader()->isLoadingInAPISense())
            request.setCachePolicy(documentLoader()->originalRequest().cachePolicy());
        else
            request.setCachePolicy(UseProtocolCachePolicy);
    } else if (loadType == FrameLoadTypeReload || loadType == FrameLoadTypeReloadFromOrigin || request.isConditional())
        request.setCachePolicy(ReloadIgnoringCacheData);
    else if (isBackForwardLoadType(loadType) && m_stateMachine.committedFirstRealDocumentLoad())
        request.setCachePolicy(ReturnCacheDataElseLoad);
        
    if (request.cachePolicy() == ReloadIgnoringCacheData) {
        if (loadType == FrameLoadTypeReload)
            request.setHTTPHeaderField("Cache-Control", "max-age=0");
        else if (loadType == FrameLoadTypeReloadFromOrigin) {
            request.setHTTPHeaderField("Cache-Control", "no-cache");
            request.setHTTPHeaderField("Pragma", "no-cache");
        }
    }
    
    if (mainResource)
        request.setHTTPAccept(defaultAcceptHeader);

    // Make sure we send the Origin header.
    addHTTPOriginIfNeeded(request, String());

    // Always try UTF-8. If that fails, try frame encoding (if any) and then the default.
    // For a newly opened frame with an empty URL, encoding() should not be used, because this methods asks decoder, which uses ISO-8859-1.
    Settings* settings = m_frame->settings();
    request.setResponseContentDispositionEncodingFallbackArray("UTF-8", activeDocumentLoader()->writer()->deprecatedFrameEncoding(), settings ? settings->defaultTextEncodingName() : String());
}

void FrameLoader::addHTTPOriginIfNeeded(ResourceRequest& request, const String& origin)
{
    if (!request.httpOrigin().isEmpty())
        return;  // Request already has an Origin header.

    // Don't send an Origin header for GET or HEAD to avoid privacy issues.
    // For example, if an intranet page has a hyperlink to an external web
    // site, we don't want to include the Origin of the request because it
    // will leak the internal host name. Similar privacy concerns have lead
    // to the widespread suppression of the Referer header at the network
    // layer.
    if (request.httpMethod() == "GET" || request.httpMethod() == "HEAD")
        return;

    // For non-GET and non-HEAD methods, always send an Origin header so the
    // server knows we support this feature.

    if (origin.isEmpty()) {
        // If we don't know what origin header to attach, we attach the value
        // for an empty origin.
        request.setHTTPOrigin(SecurityOrigin::createEmpty()->toString());
        return;
    }

    request.setHTTPOrigin(origin);
}

void FrameLoader::loadPostRequest(const ResourceRequest& inRequest, const String& referrer, const String& frameName, bool lockHistory, FrameLoadType loadType, PassRefPtr<Event> event, PassRefPtr<FormState> prpFormState)
{
    RefPtr<FormState> formState = prpFormState;

    // Previously when this method was reached, the original FrameLoadRequest had been deconstructed to build a 
    // bunch of parameters that would come in here and then be built back up to a ResourceRequest.  In case
    // any caller depends on the immutability of the original ResourceRequest, I'm rebuilding a ResourceRequest
    // from scratch as it did all along.
    const KURL& url = inRequest.url();
    RefPtr<FormData> formData = inRequest.httpBody();
    const String& contentType = inRequest.httpContentType();
    String origin = inRequest.httpOrigin();

    ResourceRequest workingResourceRequest(url);    

    if (!referrer.isEmpty())
        workingResourceRequest.setHTTPReferrer(referrer);
    workingResourceRequest.setHTTPOrigin(origin);
    workingResourceRequest.setHTTPMethod("POST");
    workingResourceRequest.setHTTPBody(formData);
    workingResourceRequest.setHTTPContentType(contentType);
    addExtraFieldsToRequest(workingResourceRequest, loadType, true, true);

    NavigationAction action(url, loadType, true, event);

    if (!frameName.isEmpty()) {
        // The search for a target frame is done earlier in the case of form submission.
        if (Frame* targetFrame = formState ? 0 : findFrameForNavigation(frameName))
            targetFrame->loader()->loadWithNavigationAction(workingResourceRequest, action, lockHistory, loadType, formState.release());
        else
            policyChecker()->checkNewWindowPolicy(action, FrameLoader::callContinueLoadAfterNewWindowPolicy, workingResourceRequest, formState.release(), frameName, this);
    } else
        loadWithNavigationAction(workingResourceRequest, action, lockHistory, loadType, formState.release());    
}

unsigned long FrameLoader::loadResourceSynchronously(const ResourceRequest& request, StoredCredentials storedCredentials, ResourceError& error, ResourceResponse& response, Vector<char>& data)
{
    String referrer = m_outgoingReferrer;
    if (SecurityOrigin::shouldHideReferrer(request.url(), referrer))
        referrer = String();
    
    ResourceRequest initialRequest = request;
    initialRequest.setTimeoutInterval(10);
    
    if (!referrer.isEmpty())
        initialRequest.setHTTPReferrer(referrer);
    addHTTPOriginIfNeeded(initialRequest, outgoingOrigin());

    if (Page* page = m_frame->page())
        initialRequest.setFirstPartyForCookies(page->mainFrame()->loader()->documentLoader()->request().url());
    initialRequest.setHTTPUserAgent(client()->userAgent(request.url()));
    
    addExtraFieldsToSubresourceRequest(initialRequest);

    unsigned long identifier = 0;    
    ResourceRequest newRequest(initialRequest);
    requestFromDelegate(newRequest, identifier, error);

    if (error.isNull()) {
        ASSERT(!newRequest.isNull());
        
#if ENABLE(OFFLINE_WEB_APPLICATIONS)
        if (!documentLoader()->applicationCacheHost()->maybeLoadSynchronously(newRequest, error, response, data)) {
#endif
            ResourceHandle::loadResourceSynchronously(networkingContext(), newRequest, storedCredentials, error, response, data);
#if ENABLE(OFFLINE_WEB_APPLICATIONS)
            documentLoader()->applicationCacheHost()->maybeLoadFallbackSynchronously(newRequest, error, response, data);
        }
#endif
    }
    int encodedDataLength = response.resourceLoadInfo() ? static_cast<int>(response.resourceLoadInfo()->encodedDataLength) : -1;
    notifier()->sendRemainingDelegateMessages(m_documentLoader.get(), identifier, response, data.size(), encodedDataLength, error);
    return identifier;
}

const ResourceRequest& FrameLoader::originalRequest() const
{
    return activeDocumentLoader()->originalRequestCopy();
}

void FrameLoader::receivedMainResourceError(const ResourceError& error, bool isComplete)
{
    // Retain because the stop may release the last reference to it.
    RefPtr<Frame> protect(m_frame);

    RefPtr<DocumentLoader> loader = activeDocumentLoader();

    if (isComplete) {
        // FIXME: Don't want to do this if an entirely new load is going, so should check
        // that both data sources on the frame are either this or nil.
        stop();
        if (m_client->shouldFallBack(error))
            handleFallbackContent();
    }

    if (m_state == FrameStateProvisional && m_provisionalDocumentLoader) {
        if (m_submittedFormURL == m_provisionalDocumentLoader->originalRequestCopy().url())
            m_submittedFormURL = KURL();
            
        // We might have made a page cache item, but now we're bailing out due to an error before we ever
        // transitioned to the new page (before WebFrameState == commit).  The goal here is to restore any state
        // so that the existing view (that wenever got far enough to replace) can continue being used.
        history()->invalidateCurrentItemCachedPage();
        
        // Call clientRedirectCancelledOrFinished here so that the frame load delegate is notified that the redirect's
        // status has changed, if there was a redirect. The frame load delegate may have saved some state about
        // the redirect in its -webView:willPerformClientRedirectToURL:delay:fireDate:forFrame:. Since we are definitely
        // not going to use this provisional resource, as it was cancelled, notify the frame load delegate that the redirect
        // has ended.
        if (m_sentRedirectNotification)
            clientRedirectCancelledOrFinished(false);
    }

    loader->mainReceivedError(error, isComplete);
}

void FrameLoader::callContinueFragmentScrollAfterNavigationPolicy(void* argument,
    const ResourceRequest& request, PassRefPtr<FormState>, bool shouldContinue)
{
    FrameLoader* loader = static_cast<FrameLoader*>(argument);
    loader->continueFragmentScrollAfterNavigationPolicy(request, shouldContinue);
}

void FrameLoader::continueFragmentScrollAfterNavigationPolicy(const ResourceRequest& request, bool shouldContinue)
{
    m_quickRedirectComing = false;

    if (!shouldContinue)
        return;

    bool isRedirect = m_quickRedirectComing || policyChecker()->loadType() == FrameLoadTypeRedirectWithLockedBackForwardList;    
    loadInSameDocument(request.url(), 0, !isRedirect);
}

bool FrameLoader::shouldScrollToAnchor(bool isFormSubmission, const String& httpMethod, FrameLoadType loadType, const KURL& url)
{
    // Should we do anchor navigation within the existing content?

    // We don't do this if we are submitting a form with method other than "GET", explicitly reloading,
    // currently displaying a frameset, or if the URL does not have a fragment.
    // These rules were originally based on what KHTML was doing in KHTMLPart::openURL.

    // FIXME: What about load types other than Standard and Reload?

    return (!isFormSubmission || equalIgnoringCase(httpMethod, "GET"))
        && loadType != FrameLoadTypeReload
        && loadType != FrameLoadTypeReloadFromOrigin
        && loadType != FrameLoadTypeSame
        && !shouldReload(m_frame->document()->url(), url)
        // We don't want to just scroll if a link from within a
        // frameset is trying to reload the frameset into _top.
        && !m_frame->document()->isFrameSet();
}

void FrameLoader::callContinueLoadAfterNavigationPolicy(void* argument,
    const ResourceRequest& request, PassRefPtr<FormState> formState, bool shouldContinue)
{
    FrameLoader* loader = static_cast<FrameLoader*>(argument);
    loader->continueLoadAfterNavigationPolicy(request, formState, shouldContinue);
}

bool FrameLoader::shouldClose()
{
    Page* page = m_frame->page();
    Chrome* chrome = page ? page->chrome() : 0;
    if (!chrome || !chrome->canRunBeforeUnloadConfirmPanel())
        return true;

    // Store all references to each subframe in advance since beforeunload's event handler may modify frame
    Vector<RefPtr<Frame> > targetFrames;
    targetFrames.append(m_frame);
    for (Frame* child = m_frame->tree()->firstChild(); child; child = child->tree()->traverseNext(m_frame))
        targetFrames.append(child);

    bool shouldClose = false;
    {
        NavigationDisablerForBeforeUnload navigationDisabler;
        size_t i;

        for (i = 0; i < targetFrames.size(); i++) {
            if (!targetFrames[i]->tree()->isDescendantOf(m_frame))
                continue;
            if (!targetFrames[i]->loader()->fireBeforeUnloadEvent(chrome))
                break;
        }

        if (i == targetFrames.size())
            shouldClose = true;
    }

    return shouldClose;
}

bool FrameLoader::fireBeforeUnloadEvent(Chrome* chrome)
{
    DOMWindow* domWindow = m_frame->existingDOMWindow();
    if (!domWindow)
        return true;

    RefPtr<Document> document = m_frame->document();
    if (!document->body())
        return true;

    RefPtr<BeforeUnloadEvent> beforeUnloadEvent = BeforeUnloadEvent::create();
    m_pageDismissalEventBeingDispatched = true;
    domWindow->dispatchEvent(beforeUnloadEvent.get(), domWindow->document());
    m_pageDismissalEventBeingDispatched = false;

    if (!beforeUnloadEvent->defaultPrevented())
        document->defaultEventHandler(beforeUnloadEvent.get());
    if (beforeUnloadEvent->result().isNull())
        return true;

    String text = document->displayStringModifiedByEncoding(beforeUnloadEvent->result());
    return chrome->runBeforeUnloadConfirmPanel(text, m_frame);
}

void FrameLoader::continueLoadAfterNavigationPolicy(const ResourceRequest&, PassRefPtr<FormState> formState, bool shouldContinue)
{
    // If we loaded an alternate page to replace an unreachableURL, we'll get in here with a
    // nil policyDataSource because loading the alternate page will have passed
    // through this method already, nested; otherwise, policyDataSource should still be set.
    ASSERT(m_policyDocumentLoader || !m_provisionalDocumentLoader->unreachableURL().isEmpty());

    bool isTargetItem = history()->provisionalItem() ? history()->provisionalItem()->isTargetItem() : false;

    // Two reasons we can't continue:
    //    1) Navigation policy delegate said we can't so request is nil. A primary case of this 
    //       is the user responding Cancel to the form repost nag sheet.
    //    2) User responded Cancel to an alert popped up by the before unload event handler.
    bool canContinue = shouldContinue && shouldClose();

    if (!canContinue) {
        // If we were waiting for a quick redirect, but the policy delegate decided to ignore it, then we 
        // need to report that the client redirect was cancelled.
        if (m_quickRedirectComing)
            clientRedirectCancelledOrFinished(false);

        setPolicyDocumentLoader(0);

        // If the navigation request came from the back/forward menu, and we punt on it, we have the 
        // problem that we have optimistically moved the b/f cursor already, so move it back.  For sanity, 
        // we only do this when punting a navigation for the target frame or top-level frame.  
        if ((isTargetItem || isLoadingMainFrame()) && isBackForwardLoadType(policyChecker()->loadType())) {
            if (Page* page = m_frame->page()) {
                Frame* mainFrame = page->mainFrame();
                if (HistoryItem* resetItem = mainFrame->loader()->history()->currentItem()) {
                    page->backForward()->setCurrentItem(resetItem);
                    m_frame->loader()->client()->updateGlobalHistoryItemForPage();
                }
            }
        }
        return;
    }

    FrameLoadType type = policyChecker()->loadType();
    // A new navigation is in progress, so don't clear the history's provisional item.
    stopAllLoaders(ShouldNotClearProvisionalItem);
    
    // <rdar://problem/6250856> - In certain circumstances on pages with multiple frames, stopAllLoaders()
    // might detach the current FrameLoader, in which case we should bail on this newly defunct load. 
    if (!m_frame->page())
        return;

#if ENABLE(JAVASCRIPT_DEBUGGER) && ENABLE(INSPECTOR)
    if (Page* page = m_frame->page()) {
        if (page->mainFrame() == m_frame)
            m_frame->page()->inspectorController()->resume();
    }
#endif

    setProvisionalDocumentLoader(m_policyDocumentLoader.get());
    m_loadType = type;
    setState(FrameStateProvisional);

    setPolicyDocumentLoader(0);

    if (isBackForwardLoadType(type) && history()->provisionalItem()->isInPageCache()) {
        loadProvisionalItemFromCachedPage();
        return;
    }

    if (formState)
        m_client->dispatchWillSubmitForm(&PolicyChecker::continueLoadAfterWillSubmitForm, formState);
    else
        continueLoadAfterWillSubmitForm();
}

void FrameLoader::callContinueLoadAfterNewWindowPolicy(void* argument,
    const ResourceRequest& request, PassRefPtr<FormState> formState, const String& frameName, const NavigationAction& action, bool shouldContinue)
{
    FrameLoader* loader = static_cast<FrameLoader*>(argument);
    loader->continueLoadAfterNewWindowPolicy(request, formState, frameName, action, shouldContinue);
}

void FrameLoader::continueLoadAfterNewWindowPolicy(const ResourceRequest& request,
    PassRefPtr<FormState> formState, const String& frameName, const NavigationAction& action, bool shouldContinue)
{
    if (!shouldContinue)
        return;

    RefPtr<Frame> frame = m_frame;
    RefPtr<Frame> mainFrame = m_client->dispatchCreatePage(action);
    if (!mainFrame)
        return;

    if (frameName != "_blank")
        mainFrame->tree()->setName(frameName);

    mainFrame->page()->setOpenedByDOM();
    mainFrame->loader()->m_client->dispatchShow();
    if (!m_suppressOpenerInNewFrame)
        mainFrame->loader()->setOpener(frame.get());
    mainFrame->loader()->loadWithNavigationAction(request, NavigationAction(), false, FrameLoadTypeStandard, formState);
}

void FrameLoader::requestFromDelegate(ResourceRequest& request, unsigned long& identifier, ResourceError& error)
{
    ASSERT(!request.isNull());

    identifier = 0;
    if (Page* page = m_frame->page()) {
        identifier = page->progress()->createUniqueIdentifier();
        notifier()->assignIdentifierToInitialRequest(identifier, m_documentLoader.get(), request);
    }

    ResourceRequest newRequest(request);
    notifier()->dispatchWillSendRequest(m_documentLoader.get(), identifier, newRequest, ResourceResponse());

    if (newRequest.isNull())
        error = cancelledError(request);
    else
        error = ResourceError();

    request = newRequest;
}

void FrameLoader::loadedResourceFromMemoryCache(const CachedResource* resource)
{
    Page* page = m_frame->page();
    if (!page)
        return;

    if (!resource->sendResourceLoadCallbacks() || m_documentLoader->haveToldClientAboutLoad(resource->url()))
        return;

    if (!page->areMemoryCacheClientCallsEnabled()) {
        InspectorInstrumentation::didLoadResourceFromMemoryCache(page, m_documentLoader.get(), resource);
        m_documentLoader->recordMemoryCacheLoadForFutureClientNotification(resource->url());
        m_documentLoader->didTellClientAboutLoad(resource->url());
        return;
    }

    ResourceRequest request(resource->url());
    if (m_client->dispatchDidLoadResourceFromMemoryCache(m_documentLoader.get(), request, resource->response(), resource->encodedSize())) {
        InspectorInstrumentation::didLoadResourceFromMemoryCache(page, m_documentLoader.get(), resource);
        m_documentLoader->didTellClientAboutLoad(resource->url());
        return;
    }

    unsigned long identifier;
    ResourceError error;
    requestFromDelegate(request, identifier, error);
    InspectorInstrumentation::markResourceAsCached(page, identifier);
    notifier()->sendRemainingDelegateMessages(m_documentLoader.get(), identifier, resource->response(), resource->encodedSize(), 0, error);
}

void FrameLoader::applyUserAgent(ResourceRequest& request)
{
    String userAgent = this->userAgent(request.url());
    ASSERT(!userAgent.isNull());
    request.setHTTPUserAgent(userAgent);
}

bool FrameLoader::shouldInterruptLoadForXFrameOptions(const String& content, const KURL& url)
{
    Frame* topFrame = m_frame->tree()->top();
    if (m_frame == topFrame)
        return false;

    if (equalIgnoringCase(content, "deny"))
        return true;

    if (equalIgnoringCase(content, "sameorigin")) {
        RefPtr<SecurityOrigin> origin = SecurityOrigin::create(url);
        if (!origin->isSameSchemeHostPort(topFrame->document()->securityOrigin()))
            return true;
    }

    return false;
}

void FrameLoader::loadProvisionalItemFromCachedPage()
{
    DocumentLoader* provisionalLoader = provisionalDocumentLoader();
    LOG(PageCache, "WebCorePageCache: Loading provisional DocumentLoader %p with URL '%s' from CachedPage", provisionalDocumentLoader(), provisionalDocumentLoader()->url().string().utf8().data());

    provisionalLoader->prepareForLoadStart();

    m_loadingFromCachedPage = true;
    
    // Should have timing data from previous time(s) the page was shown.
    ASSERT(provisionalLoader->timing()->navigationStart);
    provisionalLoader->resetTiming();
    provisionalLoader->timing()->navigationStart = currentTime();    

    provisionalLoader->setCommitted(true);
    commitProvisionalLoad();
}

bool FrameLoader::shouldTreatURLAsSameAsCurrent(const KURL& url) const
{
    if (!history()->currentItem())
        return false;
    return url == history()->currentItem()->url() || url == history()->currentItem()->originalURL();
}

void FrameLoader::checkDidPerformFirstNavigation()
{
    Page* page = m_frame->page();
    if (!page)
        return;

    if (!m_didPerformFirstNavigation && page->backForward()->currentItem() && !page->backForward()->backItem() && !page->backForward()->forwardItem()) {
        m_didPerformFirstNavigation = true;
        m_client->didPerformFirstNavigation();
    }
}

Frame* FrameLoader::findFrameForNavigation(const AtomicString& name)
{
    Frame* frame = m_frame->tree()->find(name);
    if (!shouldAllowNavigation(frame))
        return 0;
    return frame;
}

void FrameLoader::loadSameDocumentItem(HistoryItem* item)
{
    ASSERT(item->documentSequenceNumber() == history()->currentItem()->documentSequenceNumber());

    // Save user view state to the current history item here since we don't do a normal load.
    // FIXME: Does form state need to be saved here too?
    history()->saveScrollPositionAndViewStateToItem(history()->currentItem());
    if (FrameView* view = m_frame->view())
        view->setWasScrolledByUser(false);

    history()->setCurrentItem(item);
        
    // loadInSameDocument() actually changes the URL and notifies load delegates of a "fake" load
    loadInSameDocument(item->url(), item->stateObject(), false);

    // Restore user view state from the current history item here since we don't do a normal load.
    history()->restoreScrollPositionAndViewState();
}

// FIXME: This function should really be split into a couple pieces, some of
// which should be methods of HistoryController and some of which should be
// methods of FrameLoader.
void FrameLoader::loadDifferentDocumentItem(HistoryItem* item, FrameLoadType loadType)
{
    // Remember this item so we can traverse any child items as child frames load
    history()->setProvisionalItem(item);

    if (CachedPage* cachedPage = pageCache()->get(item)) {
        loadWithDocumentLoader(cachedPage->documentLoader(), loadType, 0);   
        return;
    }

    KURL itemURL = item->url();
    KURL itemOriginalURL = item->originalURL();
    KURL currentURL;
    if (documentLoader())
        currentURL = documentLoader()->url();
    RefPtr<FormData> formData = item->formData();

    bool addedExtraFields = false;
    ResourceRequest request(itemURL);

    if (!item->referrer().isNull())
        request.setHTTPReferrer(item->referrer());
    
    // If this was a repost that failed the page cache, we might try to repost the form.
    NavigationAction action;
    if (formData) {
        formData->generateFiles(m_frame->document());

        request.setHTTPMethod("POST");
        request.setHTTPBody(formData);
        request.setHTTPContentType(item->formContentType());
        RefPtr<SecurityOrigin> securityOrigin = SecurityOrigin::createFromString(item->referrer());
        addHTTPOriginIfNeeded(request, securityOrigin->toString());

        // Make sure to add extra fields to the request after the Origin header is added for the FormData case.
        // See https://bugs.webkit.org/show_bug.cgi?id=22194 for more discussion.
        addExtraFieldsToRequest(request, m_loadType, true, formData);
        addedExtraFields = true;
        
        // FIXME: Slight hack to test if the NSURL cache contains the page we're going to.
        // We want to know this before talking to the policy delegate, since it affects whether 
        // we show the DoYouReallyWantToRepost nag.
        //
        // This trick has a small bug (3123893) where we might find a cache hit, but then
        // have the item vanish when we try to use it in the ensuing nav.  This should be
        // extremely rare, but in that case the user will get an error on the navigation.
        
        if (ResourceHandle::willLoadFromCache(request, m_frame))
            action = NavigationAction(itemURL, loadType, false);
        else {
            request.setCachePolicy(ReloadIgnoringCacheData);
            action = NavigationAction(itemURL, NavigationTypeFormResubmitted);
        }
    } else {
        switch (loadType) {
            case FrameLoadTypeReload:
            case FrameLoadTypeReloadFromOrigin:
                request.setCachePolicy(ReloadIgnoringCacheData);
                break;
            case FrameLoadTypeBack:
            case FrameLoadTypeForward:
            case FrameLoadTypeIndexedBackForward:
                // If the first load within a frame is a navigation within a back/forward list that was attached 
                // without any of the items being loaded then we should use the default caching policy (<rdar://problem/8131355>).
                if (m_stateMachine.committedFirstRealDocumentLoad() && !itemURL.protocolIs("https"))
                    request.setCachePolicy(ReturnCacheDataElseLoad);
                break;
            case FrameLoadTypeStandard:
            case FrameLoadTypeRedirectWithLockedBackForwardList:
                break;
            case FrameLoadTypeSame:
            default:
                ASSERT_NOT_REACHED();
        }

        action = NavigationAction(itemOriginalURL, loadType, false);
    }
    
    if (!addedExtraFields)
        addExtraFieldsToRequest(request, m_loadType, true, formData);

    loadWithNavigationAction(request, action, false, loadType, 0);
}

// Loads content into this frame, as specified by history item
void FrameLoader::loadItem(HistoryItem* item, FrameLoadType loadType)
{
    HistoryItem* currentItem = history()->currentItem();
    bool sameDocumentNavigation = currentItem && item->shouldDoSameDocumentNavigationTo(currentItem);

    if (sameDocumentNavigation)
        loadSameDocumentItem(item);
    else
        loadDifferentDocumentItem(item, loadType);
}

void FrameLoader::mainReceivedCompleteError(DocumentLoader* loader, const ResourceError&)
{
    loader->setPrimaryLoadComplete(true);
    m_client->dispatchDidLoadMainResource(activeDocumentLoader());
    checkCompleted();
    if (m_frame->page())
        checkLoadComplete();
}

ResourceError FrameLoader::cancelledError(const ResourceRequest& request) const
{
    ResourceError error = m_client->cancelledError(request);
    error.setIsCancellation(true);
    return error;
}

void FrameLoader::setTitle(const StringWithDirection& title)
{
    documentLoader()->setTitle(title);
}

String FrameLoader::referrer() const
{
    return m_documentLoader ? m_documentLoader->request().httpReferrer() : "";
}

void FrameLoader::dispatchDocumentElementAvailable()
{
    m_frame->injectUserScripts(InjectAtDocumentStart);
    m_client->documentElementAvailable();
}

void FrameLoader::dispatchDidClearWindowObjectsInAllWorlds()
{
    if (!m_frame->script()->canExecuteScripts(NotAboutToExecuteScript))
        return;

    Vector<DOMWrapperWorld*> worlds;
    ScriptController::getAllWorlds(worlds);
    for (size_t i = 0; i < worlds.size(); ++i)
        dispatchDidClearWindowObjectInWorld(worlds[i]);
}

void FrameLoader::dispatchDidClearWindowObjectInWorld(DOMWrapperWorld* world)
{
    if (!m_frame->script()->canExecuteScripts(NotAboutToExecuteScript) || !m_frame->script()->existingWindowShell(world))
        return;

    m_client->dispatchDidClearWindowObjectInWorld(world);

#if ENABLE(INSPECTOR)
    if (Page* page = m_frame->page())
        page->inspectorController()->didClearWindowObjectInWorld(m_frame, world);
#endif

    InspectorInstrumentation::didClearWindowObjectInWorld(m_frame, world);
}

void FrameLoader::updateSandboxFlags()
{
    SandboxFlags flags = m_forcedSandboxFlags;
    if (Frame* parentFrame = m_frame->tree()->parent())
        flags |= parentFrame->loader()->sandboxFlags();
    if (HTMLFrameOwnerElement* ownerElement = m_frame->ownerElement())
        flags |= ownerElement->sandboxFlags();

    if (m_sandboxFlags == flags)
        return;

    m_sandboxFlags = flags;

    for (Frame* child = m_frame->tree()->firstChild(); child; child = child->tree()->nextSibling())
        child->loader()->updateSandboxFlags();
}

void FrameLoader::didChangeTitle(DocumentLoader* loader)
{
    m_client->didChangeTitle(loader);

    if (loader == m_documentLoader) {
        // Must update the entries in the back-forward list too.
        history()->setCurrentItemTitle(loader->title());
        // This must go through the WebFrame because it has the right notion of the current b/f item.
        m_client->setTitle(loader->title(), loader->urlForHistory());
        m_client->setMainFrameDocumentReady(true); // update observers with new DOMDocument
        m_client->dispatchDidReceiveTitle(loader->title());
    }
}

void FrameLoader::didChangeIcons(DocumentLoader* loader, IconType type)
{
    if (loader == m_documentLoader)
        m_client->dispatchDidChangeIcons(type);
}

void FrameLoader::dispatchDidCommitLoad()
{
    if (m_stateMachine.creatingInitialEmptyDocument())
        return;

    m_client->dispatchDidCommitLoad();

    InspectorInstrumentation::didCommitLoad(m_frame, m_documentLoader.get());
}

void FrameLoader::tellClientAboutPastMemoryCacheLoads()
{
    ASSERT(m_frame->page());
    ASSERT(m_frame->page()->areMemoryCacheClientCallsEnabled());

    if (!m_documentLoader)
        return;

    Vector<String> pastLoads;
    m_documentLoader->takeMemoryCacheLoadsForClientNotification(pastLoads);

    size_t size = pastLoads.size();
    for (size_t i = 0; i < size; ++i) {
        CachedResource* resource = memoryCache()->resourceForURL(KURL(ParsedURLString, pastLoads[i]));

        // FIXME: These loads, loaded from cache, but now gone from the cache by the time
        // Page::setMemoryCacheClientCallsEnabled(true) is called, will not be seen by the client.
        // Consider if there's some efficient way of remembering enough to deliver this client call.
        // We have the URL, but not the rest of the response or the length.
        if (!resource)
            continue;

        ResourceRequest request(resource->url());
        m_client->dispatchDidLoadResourceFromMemoryCache(m_documentLoader.get(), request, resource->response(), resource->encodedSize());
    }
}

NetworkingContext* FrameLoader::networkingContext() const
{
    return m_networkingContext.get();
}

bool FrameLoaderClient::hasHTMLView() const
{
    return true;
}

Frame* createWindow(Frame* openerFrame, Frame* lookupFrame, const FrameLoadRequest& request, const WindowFeatures& features, bool& created)
{
    ASSERT(!features.dialog || request.frameName().isEmpty());

    if (!request.frameName().isEmpty() && request.frameName() != "_blank") {
        Frame* frame = lookupFrame->tree()->find(request.frameName());
        if (frame && openerFrame->loader()->shouldAllowNavigation(frame)) {
            if (Page* page = frame->page())
                page->chrome()->focus();
            created = false;
            return frame;
        }
    }

    // Sandboxed frames cannot open new auxiliary browsing contexts.
    if (isDocumentSandboxed(openerFrame, SandboxNavigation))
        return 0;

    // FIXME: Setting the referrer should be the caller's responsibility.
    FrameLoadRequest requestWithReferrer = request;
    requestWithReferrer.resourceRequest().setHTTPReferrer(openerFrame->loader()->outgoingReferrer());
    FrameLoader::addHTTPOriginIfNeeded(requestWithReferrer.resourceRequest(), openerFrame->loader()->outgoingOrigin());

    Page* oldPage = openerFrame->page();
    if (!oldPage)
        return 0;

    NavigationAction action;
    Page* page = oldPage->chrome()->createWindow(openerFrame, requestWithReferrer, features, action);
    if (!page)
        return 0;

    Frame* frame = page->mainFrame();
    if (request.frameName() != "_blank")
        frame->tree()->setName(request.frameName());

    page->chrome()->setToolbarsVisible(features.toolBarVisible || features.locationBarVisible);
    page->chrome()->setStatusbarVisible(features.statusBarVisible);
    page->chrome()->setScrollbarsVisible(features.scrollbarsVisible);
    page->chrome()->setMenubarVisible(features.menuBarVisible);
    page->chrome()->setResizable(features.resizable);

    // 'x' and 'y' specify the location of the window, while 'width' and 'height'
    // specify the size of the page. We can only resize the window, so
    // adjust for the difference between the window size and the page size.

    FloatRect windowRect = page->chrome()->windowRect();
    FloatSize pageSize = page->chrome()->pageRect().size();
    if (features.xSet)
        windowRect.setX(features.x);
    if (features.ySet)
        windowRect.setY(features.y);
    if (features.widthSet)
        windowRect.setWidth(features.width + (windowRect.width() - pageSize.width()));
    if (features.heightSet)
        windowRect.setHeight(features.height + (windowRect.height() - pageSize.height()));
    page->chrome()->setWindowRect(windowRect);

    page->chrome()->show();

    created = true;
    return frame;
}

} // namespace WebCore