Source/core/page/Page.cpp

/*
 * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All Rights Reserved.
 * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"
#include "core/page/Page.h"

#include "core/dom/ClientRectList.h"
#include "core/dom/DocumentMarkerController.h"
#include "core/dom/DocumentStyleSheetCollection.h"
#include "core/dom/Event.h"
#include "core/dom/EventNames.h"
#include "core/dom/VisitedLinkState.h"
#include "core/dom/WebCoreMemoryInstrumentation.h"
#include "core/editing/Editor.h"
#include "core/history/BackForwardController.h"
#include "core/history/HistoryItem.h"
#include "core/inspector/InspectorController.h"
#include "core/inspector/InspectorInstrumentation.h"
#include "core/loader/FrameLoader.h"
#include "core/loader/ProgressTracker.h"
#include "core/page/AutoscrollController.h"
#include "core/page/Chrome.h"
#include "core/page/ContextMenuController.h"
#include "core/page/DOMTimer.h"
#include "core/page/DragController.h"
#include "core/page/FocusController.h"
#include "core/page/Frame.h"
#include "core/page/FrameTree.h"
#include "core/page/FrameView.h"
#include "core/page/PageConsole.h"
#include "core/page/PageGroup.h"
#include "core/page/PointerLockController.h"
#include "core/page/Settings.h"
#include "core/page/scrolling/ScrollingCoordinator.h"
#include "core/platform/network/NetworkStateNotifier.h"
#include "core/plugins/PluginData.h"
#include "core/rendering/RenderArena.h"
#include "core/rendering/RenderTheme.h"
#include "core/rendering/RenderView.h"
#include "core/storage/StorageNamespace.h"
#include "wtf/HashMap.h"
#include "wtf/MemoryInstrumentationHashSet.h"
#include "wtf/RefCountedLeakCounter.h"
#include "wtf/StdLibExtras.h"
#include "wtf/text/Base64.h"

namespace WebCore {

static HashSet<Page*>* allPages;

DEFINE_DEBUG_ONLY_GLOBAL(WTF::RefCountedLeakCounter, pageCounter, ("Page"));

static void networkStateChanged()
{
    Vector<RefPtr<Frame> > frames;

    // Get all the frames of all the pages in all the page groups
    HashSet<Page*>::iterator end = allPages->end();
    for (HashSet<Page*>::iterator it = allPages->begin(); it != end; ++it) {
        for (Frame* frame = (*it)->mainFrame(); frame; frame = frame->tree()->traverseNext())
            frames.append(frame);
        InspectorInstrumentation::networkStateChanged(*it);
    }

    AtomicString eventName = networkStateNotifier().onLine() ? eventNames().onlineEvent : eventNames().offlineEvent;
    for (unsigned i = 0; i < frames.size(); i++)
        frames[i]->document()->dispatchWindowEvent(Event::create(eventName, false, false));
}

float deviceScaleFactor(Frame* frame)
{
    if (!frame)
        return 1;
    Page* page = frame->page();
    if (!page)
        return 1;
    return page->deviceScaleFactor();
}

Page::Page(PageClients& pageClients)
    : m_autoscrollController(AutoscrollController::create())
    , m_chrome(Chrome::create(this, pageClients.chromeClient))
    , m_dragCaretController(DragCaretController::create())
    , m_dragController(DragController::create(this, pageClients.dragClient))
    , m_focusController(FocusController::create(this))
    , m_contextMenuController(ContextMenuController::create(this, pageClients.contextMenuClient))
    , m_inspectorController(InspectorController::create(this, pageClients.inspectorClient))
    , m_pointerLockController(PointerLockController::create(this))
    , m_settings(Settings::create(this))
    , m_progress(ProgressTracker::create())
    , m_backForwardController(BackForwardController::create(this, pageClients.backForwardClient))
    , m_theme(RenderTheme::themeForPage(this))
    , m_editorClient(pageClients.editorClient)
    , m_validationMessageClient(0)
    , m_subframeCount(0)
    , m_openedByDOM(false)
    , m_tabKeyCyclesThroughElements(true)
    , m_defersLoading(false)
    , m_defersLoadingCallCount(0)
    , m_pageScaleFactor(1)
    , m_deviceScaleFactor(1)
    , m_didLoadUserStyleSheet(false)
    , m_userStyleSheetModificationTime(0)
    , m_group(0)
    , m_timerAlignmentInterval(DOMTimer::visiblePageAlignmentInterval())
    , m_isInWindow(true)
    , m_visibilityState(PageVisibilityStateVisible)
    , m_isCursorVisible(true)
    , m_layoutMilestones(0)
    , m_isCountingRelevantRepaintedObjects(false)
#ifndef NDEBUG
    , m_isPainting(false)
#endif
    , m_console(PageConsole::create(this))
{
    ASSERT(m_editorClient);

    if (!allPages) {
        allPages = new HashSet<Page*>;

        networkStateNotifier().setNetworkStateChangedFunction(networkStateChanged);
    }

    ASSERT(!allPages->contains(this));
    allPages->add(this);

#ifndef NDEBUG
    pageCounter.increment();
#endif
}

Page::~Page()
{
    m_mainFrame->setView(0);
    clearPageGroup();
    allPages->remove(this);

    for (Frame* frame = mainFrame(); frame; frame = frame->tree()->traverseNext()) {
        frame->willDetachPage();
        frame->detachFromPage();
    }

    m_inspectorController->inspectedPageDestroyed();

    if (m_scrollingCoordinator)
        m_scrollingCoordinator->pageDestroyed();

    backForward()->close();

#ifndef NDEBUG
    pageCounter.decrement();
#endif
}

ArenaSize Page::renderTreeSize() const
{
    ArenaSize total(0, 0);
    for (Frame* frame = mainFrame(); frame; frame = frame->tree()->traverseNext()) {
        if (!frame->document())
            continue;
        if (RenderArena* arena = frame->document()->renderArena()) {
            total.treeSize += arena->totalRenderArenaSize();
            total.allocated += arena->totalRenderArenaAllocatedBytes();
        }
    }
    return total;
}

ViewportArguments Page::viewportArguments() const
{
    return mainFrame() && mainFrame()->document() ? mainFrame()->document()->viewportArguments() : ViewportArguments();
}

bool Page::autoscrollInProgress() const
{
    return m_autoscrollController->autoscrollInProgress();
}

bool Page::autoscrollInProgress(const RenderBox* renderer) const
{
    return m_autoscrollController->autoscrollInProgress(renderer);
}

bool Page::panScrollInProgress() const
{
    return m_autoscrollController->panScrollInProgress();
}

void Page::startAutoscrollForSelection(RenderObject* renderer)
{
    return m_autoscrollController->startAutoscrollForSelection(renderer);
}

void Page::stopAutoscrollIfNeeded(RenderObject* renderer)
{
    m_autoscrollController->stopAutoscrollIfNeeded(renderer);
}


void Page::stopAutoscrollTimer()
{
    m_autoscrollController->stopAutoscrollTimer();
}

void Page::updateAutoscrollRenderer()
{
    m_autoscrollController->updateAutoscrollRenderer();
}

void Page::updateDragAndDrop(Node* dropTargetNode, const IntPoint& eventPosition, double eventTime)
{
    m_autoscrollController->updateDragAndDrop(dropTargetNode, eventPosition, eventTime);
}

#if OS(WINDOWS)
void Page::handleMouseReleaseForPanScrolling(Frame* frame, const PlatformMouseEvent& point)
{
    m_autoscrollController->handleMouseReleaseForPanScrolling(frame, point);
}

void Page::startPanScrolling(RenderBox* renderer, const IntPoint& point)
{
    m_autoscrollController->startPanScrolling(renderer, point);
}
#endif


ScrollingCoordinator* Page::scrollingCoordinator()
{
    if (!m_scrollingCoordinator && m_settings->scrollingCoordinatorEnabled())
        m_scrollingCoordinator = ScrollingCoordinator::create(this);

    return m_scrollingCoordinator.get();
}

String Page::mainThreadScrollingReasonsAsText()
{
    if (Document* document = m_mainFrame->document())
        document->updateLayout();

    if (ScrollingCoordinator* scrollingCoordinator = this->scrollingCoordinator())
        return scrollingCoordinator->mainThreadScrollingReasonsAsText();

    return String();
}

PassRefPtr<ClientRectList> Page::nonFastScrollableRects(const Frame* frame)
{
    if (Document* document = m_mainFrame->document())
        document->updateLayout();

    Vector<IntRect> rects;
    if (ScrollingCoordinator* scrollingCoordinator = this->scrollingCoordinator())
        rects = scrollingCoordinator->computeShouldHandleScrollGestureOnMainThreadRegion(frame, IntPoint()).rects();

    Vector<FloatQuad> quads(rects.size());
    for (size_t i = 0; i < rects.size(); ++i)
        quads[i] = FloatRect(rects[i]);
    return ClientRectList::create(quads);
}

void Page::setMainFrame(PassRefPtr<Frame> mainFrame)
{
    ASSERT(!m_mainFrame); // Should only be called during initialization
    m_mainFrame = mainFrame;
}

bool Page::openedByDOM() const
{
    return m_openedByDOM;
}

void Page::setOpenedByDOM()
{
    m_openedByDOM = true;
}

bool Page::goBack()
{
    HistoryItem* item = backForward()->backItem();

    if (item) {
        goToItem(item);
        return true;
    }
    return false;
}

bool Page::goForward()
{
    HistoryItem* item = backForward()->forwardItem();

    if (item) {
        goToItem(item);
        return true;
    }
    return false;
}

void Page::goBackOrForward(int distance)
{
    if (distance == 0)
        return;

    HistoryItem* item = backForward()->itemAtIndex(distance);
    if (!item) {
        if (distance > 0) {
            if (int forwardCount = backForward()->forwardCount())
                item = backForward()->itemAtIndex(forwardCount);
        } else {
            if (int backCount = backForward()->backCount())
                item = backForward()->itemAtIndex(-backCount);
        }
    }

    if (!item)
        return;

    goToItem(item);
}

void Page::goToItem(HistoryItem* item)
{
    // stopAllLoaders may end up running onload handlers, which could cause further history traversals that may lead to the passed in HistoryItem
    // being deref()-ed. Make sure we can still use it with HistoryController::goToItem later.
    RefPtr<HistoryItem> protector(item);

    if (m_mainFrame->loader()->history()->shouldStopLoadingForHistoryItem(item))
        m_mainFrame->loader()->stopAllLoaders();

    m_mainFrame->loader()->history()->goToItem(item);
}

int Page::getHistoryLength()
{
    return backForward()->backCount() + 1 + backForward()->forwardCount();
}

void Page::clearPageGroup()
{
    if (!m_group)
        return;
    m_group->removePage(this);
    m_group = 0;
}

void Page::setGroupType(PageGroupType type)
{
    clearPageGroup();

    switch (type) {
    case InspectorPageGroup:
        m_group = PageGroup::inspectorGroup();
        break;
    case PrivatePageGroup:
        m_group = PageGroup::create();
        break;
    case SharedPageGroup:
        m_group = PageGroup::sharedGroup();
        break;
    }

    m_group->addPage(this);
}

void Page::scheduleForcedStyleRecalcForAllPages()
{
    if (!allPages)
        return;
    HashSet<Page*>::iterator end = allPages->end();
    for (HashSet<Page*>::iterator it = allPages->begin(); it != end; ++it)
        for (Frame* frame = (*it)->mainFrame(); frame; frame = frame->tree()->traverseNext())
            frame->document()->scheduleForcedStyleRecalc();
}

void Page::setNeedsRecalcStyleInAllFrames()
{
    for (Frame* frame = mainFrame(); frame; frame = frame->tree()->traverseNext())
        frame->document()->styleResolverChanged(DeferRecalcStyle);
}

void Page::refreshPlugins(bool reload)
{
    if (!allPages)
        return;

    PluginData::refresh();

    Vector<RefPtr<Frame> > framesNeedingReload;

    HashSet<Page*>::iterator end = allPages->end();
    for (HashSet<Page*>::iterator it = allPages->begin(); it != end; ++it) {
        Page* page = *it;

        // Clear out the page's plug-in data.
        if (page->m_pluginData)
            page->m_pluginData = 0;

        if (!reload)
            continue;

        for (Frame* frame = (*it)->mainFrame(); frame; frame = frame->tree()->traverseNext()) {
            if (frame->loader()->subframeLoader()->containsPlugins())
                framesNeedingReload.append(frame);
        }
    }

    for (size_t i = 0; i < framesNeedingReload.size(); ++i)
        framesNeedingReload[i]->loader()->reload();
}

PluginData* Page::pluginData() const
{
    if (!mainFrame()->loader()->subframeLoader()->allowPlugins(NotAboutToInstantiatePlugin))
        return 0;
    if (!m_pluginData)
        m_pluginData = PluginData::create(this);
    return m_pluginData.get();
}

static Frame* incrementFrame(Frame* curr, bool forward, bool wrapFlag)
{
    return forward
        ? curr->tree()->traverseNextWithWrap(wrapFlag)
        : curr->tree()->traversePreviousWithWrap(wrapFlag);
}

void Page::unmarkAllTextMatches()
{
    if (!mainFrame())
        return;

    Frame* frame = mainFrame();
    do {
        frame->document()->markers()->removeMarkers(DocumentMarker::TextMatch);
        frame = incrementFrame(frame, true, false);
    } while (frame);
}

void Page::setDefersLoading(bool defers)
{
    ASSERT(!m_defersLoadingCallCount);
    if (defers == m_defersLoading)
        return;

    m_defersLoading = defers;
    for (Frame* frame = mainFrame(); frame; frame = frame->tree()->traverseNext())
        frame->loader()->setDefersLoading(defers);
}

void Page::setPageScaleFactor(float scale, const IntPoint& origin)
{
    FrameView* view = mainFrame()->view();

    bool oldProgrammaticScroll = view->inProgrammaticScroll();
    view->setInProgrammaticScroll(false);

    if (scale != m_pageScaleFactor) {
        m_pageScaleFactor = scale;

        if (view)
            view->setVisibleContentScaleFactor(scale);

        mainFrame()->deviceOrPageScaleFactorChanged();

        if (view)
            view->setViewportConstrainedObjectsNeedLayout();
    }

    if (view && view->scrollPosition() != origin)
        view->notifyScrollPositionChanged(origin);

    view->setInProgrammaticScroll(oldProgrammaticScroll);
}

void Page::setDeviceScaleFactor(float scaleFactor)
{
    if (m_deviceScaleFactor == scaleFactor)
        return;

    m_deviceScaleFactor = scaleFactor;
    setNeedsRecalcStyleInAllFrames();

    if (mainFrame())
        mainFrame()->deviceOrPageScaleFactorChanged();
}

void Page::setPagination(const Pagination& pagination)
{
    if (m_pagination == pagination)
        return;

    m_pagination = pagination;

    setNeedsRecalcStyleInAllFrames();
}

void Page::setIsInWindow(bool isInWindow)
{
    if (m_isInWindow == isInWindow)
        return;

    m_isInWindow = isInWindow;

    for (Frame* frame = mainFrame(); frame; frame = frame->tree()->traverseNext()) {
        if (FrameView* frameView = frame->view())
            frameView->setIsInWindow(isInWindow);
    }
}

void Page::userStyleSheetLocationChanged()
{
    // FIXME: Eventually we will move to a model of just being handed the sheet
    // text instead of loading the URL ourselves.
    KURL url = m_settings->userStyleSheetLocation();

    m_didLoadUserStyleSheet = false;
    m_userStyleSheet = String();
    m_userStyleSheetModificationTime = 0;

    // Data URLs with base64-encoded UTF-8 style sheets are common. We can process them
    // synchronously and avoid using a loader.
    if (url.protocolIsData() && url.string().startsWith("data:text/css;charset=utf-8;base64,")) {
        m_didLoadUserStyleSheet = true;

        Vector<char> styleSheetAsUTF8;
        if (base64Decode(decodeURLEscapeSequences(url.string().substring(35)), styleSheetAsUTF8, Base64IgnoreWhitespace))
            m_userStyleSheet = String::fromUTF8(styleSheetAsUTF8.data(), styleSheetAsUTF8.size());
    }

    for (Frame* frame = mainFrame(); frame; frame = frame->tree()->traverseNext()) {
        if (frame->document())
            frame->document()->styleSheetCollection()->updatePageUserSheet();
    }
}

const String& Page::userStyleSheet() const
{
    return m_userStyleSheet;
}

void Page::allVisitedStateChanged(PageGroup* group)
{
    ASSERT(group);
    if (!allPages)
        return;

    HashSet<Page*>::iterator pagesEnd = allPages->end();
    for (HashSet<Page*>::iterator it = allPages->begin(); it != pagesEnd; ++it) {
        Page* page = *it;
        if (page->m_group != group)
            continue;
        for (Frame* frame = page->m_mainFrame.get(); frame; frame = frame->tree()->traverseNext())
            frame->document()->visitedLinkState()->invalidateStyleForAllLinks();
    }
}

void Page::visitedStateChanged(PageGroup* group, LinkHash linkHash)
{
    ASSERT(group);
    if (!allPages)
        return;

    HashSet<Page*>::iterator pagesEnd = allPages->end();
    for (HashSet<Page*>::iterator it = allPages->begin(); it != pagesEnd; ++it) {
        Page* page = *it;
        if (page->m_group != group)
            continue;
        for (Frame* frame = page->m_mainFrame.get(); frame; frame = frame->tree()->traverseNext())
            frame->document()->visitedLinkState()->invalidateStyleForLink(linkHash);
    }
}

StorageNamespace* Page::sessionStorage(bool optionalCreate)
{
    if (!m_sessionStorage && optionalCreate)
        m_sessionStorage = StorageNamespace::sessionStorageNamespace(this);
    return m_sessionStorage.get();
}

void Page::setTimerAlignmentInterval(double interval)
{
    if (interval == m_timerAlignmentInterval)
        return;

    m_timerAlignmentInterval = interval;
    for (Frame* frame = mainFrame(); frame; frame = frame->tree()->traverseNextWithWrap(false)) {
        if (frame->document())
            frame->document()->didChangeTimerAlignmentInterval();
    }
}

double Page::timerAlignmentInterval() const
{
    return m_timerAlignmentInterval;
}

void Page::dnsPrefetchingStateChanged()
{
    for (Frame* frame = mainFrame(); frame; frame = frame->tree()->traverseNext())
        frame->document()->initDNSPrefetch();
}

#if !ASSERT_DISABLED
void Page::checkSubframeCountConsistency() const
{
    ASSERT(m_subframeCount >= 0);

    int subframeCount = 0;
    for (Frame* frame = mainFrame(); frame; frame = frame->tree()->traverseNext())
        ++subframeCount;

    ASSERT(m_subframeCount + 1 == subframeCount);
}
#endif

void Page::setVisibilityState(PageVisibilityState visibilityState, bool isInitialState)
{
    if (m_visibilityState == visibilityState)
        return;
    m_visibilityState = visibilityState;

    if (visibilityState == WebCore::PageVisibilityStateHidden)
        setTimerAlignmentInterval(DOMTimer::hiddenPageAlignmentInterval());
    else
        setTimerAlignmentInterval(DOMTimer::visiblePageAlignmentInterval());

    if (!isInitialState && m_mainFrame)
        m_mainFrame->dispatchVisibilityStateChangeEvent();
}

PageVisibilityState Page::visibilityState() const
{
    return m_visibilityState;
}

void Page::addLayoutMilestones(LayoutMilestones milestones)
{
    // In the future, we may want a function that replaces m_layoutMilestones instead of just adding to it.
    m_layoutMilestones |= milestones;
}

// These are magical constants that might be tweaked over time.
static double gMinimumPaintedAreaRatio = 0.1;
static double gMaximumUnpaintedAreaRatio = 0.04;

bool Page::isCountingRelevantRepaintedObjects() const
{
    return m_isCountingRelevantRepaintedObjects && (m_layoutMilestones & DidHitRelevantRepaintedObjectsAreaThreshold);
}

void Page::startCountingRelevantRepaintedObjects()
{
    // Reset everything in case we didn't hit the threshold last time.
    resetRelevantPaintedObjectCounter();

    m_isCountingRelevantRepaintedObjects = true;
}

void Page::resetRelevantPaintedObjectCounter()
{
    m_isCountingRelevantRepaintedObjects = false;
    m_relevantUnpaintedRenderObjects.clear();
    m_topRelevantPaintedRegion = Region();
    m_bottomRelevantPaintedRegion = Region();
    m_relevantUnpaintedRegion = Region();
}

static LayoutRect relevantViewRect(RenderView* view)
{
    // DidHitRelevantRepaintedObjectsAreaThreshold is a LayoutMilestone intended to indicate that
    // a certain relevant amount of content has been drawn to the screen. This is the rect that
    // has been determined to be relevant in the context of this goal. We may choose to tweak
    // the rect over time, much like we may choose to tweak gMinimumPaintedAreaRatio and
    // gMaximumUnpaintedAreaRatio. But this seems to work well right now.
    LayoutRect relevantViewRect = LayoutRect(0, 0, 980, 1300);

    LayoutRect viewRect = view->viewRect();
    // If the viewRect is wider than the relevantViewRect, center the relevantViewRect.
    if (viewRect.width() > relevantViewRect.width())
        relevantViewRect.setX((viewRect.width() - relevantViewRect.width()) / 2);

    return relevantViewRect;
}

void Page::addRelevantRepaintedObject(RenderObject* object, const LayoutRect& objectPaintRect)
{
    if (!isCountingRelevantRepaintedObjects())
        return;

    // Objects inside sub-frames are not considered to be relevant.
    if (object->document()->frame() != mainFrame())
        return;

    RenderView* view = object->view();
    if (!view)
        return;

    LayoutRect relevantRect = relevantViewRect(view);

    // The objects are only relevant if they are being painted within the viewRect().
    if (!objectPaintRect.intersects(pixelSnappedIntRect(relevantRect)))
        return;

    IntRect snappedPaintRect = pixelSnappedIntRect(objectPaintRect);

    // If this object was previously counted as an unpainted object, remove it from that HashSet
    // and corresponding Region. FIXME: This doesn't do the right thing if the objects overlap.
    HashSet<RenderObject*>::iterator it = m_relevantUnpaintedRenderObjects.find(object);
    if (it != m_relevantUnpaintedRenderObjects.end()) {
        m_relevantUnpaintedRenderObjects.remove(it);
        m_relevantUnpaintedRegion.subtract(snappedPaintRect);
    }

    // Split the relevantRect into a top half and a bottom half. Making sure we have coverage in
    // both halves helps to prevent cases where we have a fully loaded menu bar or masthead with
    // no content beneath that.
    LayoutRect topRelevantRect = relevantRect;
    topRelevantRect.contract(LayoutSize(0, relevantRect.height() / 2));
    LayoutRect bottomRelevantRect = topRelevantRect;
    bottomRelevantRect.setY(relevantRect.height() / 2);

    // If the rect straddles both Regions, split it appropriately.
    if (topRelevantRect.intersects(snappedPaintRect) && bottomRelevantRect.intersects(snappedPaintRect)) {
        IntRect topIntersection = snappedPaintRect;
        topIntersection.intersect(pixelSnappedIntRect(topRelevantRect));
        m_topRelevantPaintedRegion.unite(topIntersection);

        IntRect bottomIntersection = snappedPaintRect;
        bottomIntersection.intersect(pixelSnappedIntRect(bottomRelevantRect));
        m_bottomRelevantPaintedRegion.unite(bottomIntersection);
    } else if (topRelevantRect.intersects(snappedPaintRect))
        m_topRelevantPaintedRegion.unite(snappedPaintRect);
    else
        m_bottomRelevantPaintedRegion.unite(snappedPaintRect);

    float topPaintedArea = m_topRelevantPaintedRegion.totalArea();
    float bottomPaintedArea = m_bottomRelevantPaintedRegion.totalArea();
    float viewArea = relevantRect.width() * relevantRect.height();

    float ratioThatIsPaintedOnTop = topPaintedArea / viewArea;
    float ratioThatIsPaintedOnBottom = bottomPaintedArea / viewArea;
    float ratioOfViewThatIsUnpainted = m_relevantUnpaintedRegion.totalArea() / viewArea;

    if (ratioThatIsPaintedOnTop > (gMinimumPaintedAreaRatio / 2) && ratioThatIsPaintedOnBottom > (gMinimumPaintedAreaRatio / 2)
        && ratioOfViewThatIsUnpainted < gMaximumUnpaintedAreaRatio) {
        m_isCountingRelevantRepaintedObjects = false;
        resetRelevantPaintedObjectCounter();
        if (Frame* frame = mainFrame())
            frame->loader()->didLayout(DidHitRelevantRepaintedObjectsAreaThreshold);
    }
}

void Page::addRelevantUnpaintedObject(RenderObject* object, const LayoutRect& objectPaintRect)
{
    if (!isCountingRelevantRepaintedObjects())
        return;

    // The objects are only relevant if they are being painted within the relevantViewRect().
    if (RenderView* view = object->view()) {
        if (!objectPaintRect.intersects(pixelSnappedIntRect(relevantViewRect(view))))
            return;
    }

    m_relevantUnpaintedRenderObjects.add(object);
    m_relevantUnpaintedRegion.unite(pixelSnappedIntRect(objectPaintRect));
}

void Page::reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
{
    MemoryClassInfo info(memoryObjectInfo, this, WebCoreMemoryTypes::Page);
    info.addMember(m_chrome, "chrome");
    info.addMember(m_dragCaretController, "dragCaretController");

    info.addMember(m_dragController, "dragController");
    info.addMember(m_focusController, "focusController");
    info.addMember(m_contextMenuController, "contextMenuController");
    info.addMember(m_inspectorController, "inspectorController");
    info.addMember(m_pointerLockController, "pointerLockController");
    info.addMember(m_scrollingCoordinator, "scrollingCoordinator");
    info.addMember(m_settings, "settings");
    info.addMember(m_progress, "progress");
    info.addMember(m_backForwardController, "backForwardController");
    info.addMember(m_mainFrame, "mainFrame");
    info.addMember(m_pluginData, "pluginData");
    info.addMember(m_theme, "theme");
    info.addMember(m_UseCounter, "UseCounter");
    info.addMember(m_pagination, "pagination");
    info.addMember(m_userStyleSheet, "userStyleSheet");
    info.addMember(m_group, "group");
    info.addMember(m_sessionStorage, "sessionStorage");
    info.addMember(m_relevantUnpaintedRenderObjects, "relevantUnpaintedRenderObjects");
    info.addMember(m_topRelevantPaintedRegion, "relevantPaintedRegion");
    info.addMember(m_bottomRelevantPaintedRegion, "relevantPaintedRegion");
    info.addMember(m_relevantUnpaintedRegion, "relevantUnpaintedRegion");

    info.ignoreMember(m_editorClient);
    info.ignoreMember(m_validationMessageClient);
}

void Page::addMultisamplingChangedObserver(MultisamplingChangedObserver* observer)
{
    m_multisamplingChangedObservers.add(observer);
}

void Page::removeMultisamplingChangedObserver(MultisamplingChangedObserver* observer)
{
    m_multisamplingChangedObservers.remove(observer);
}

void Page::multisamplingChanged()
{
    HashSet<MultisamplingChangedObserver*>::iterator stop = m_multisamplingChangedObservers.end();
    for (HashSet<MultisamplingChangedObserver*>::iterator it = m_multisamplingChangedObservers.begin(); it != stop; ++it)
        (*it)->multisamplingChanged(m_settings->openGLMultisamplingEnabled());
}

Page::PageClients::PageClients()
    : chromeClient(0)
    , contextMenuClient(0)
    , editorClient(0)
    , dragClient(0)
    , inspectorClient(0)
{
}

Page::PageClients::~PageClients()
{
}

} // namespace WebCore