flutter_flutter/sky/engine/core/rendering/RenderObject.cpp

/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2000 Dirk Mueller (mueller@kde.org)
 *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
 * Copyright (C) 2009 Google Inc. All rights reserved.
 * Copyright (C) 2009 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 "sky/engine/core/rendering/RenderObject.h"

#include <algorithm>
#include "gen/sky/platform/RuntimeEnabledFeatures.h"
#include "sky/engine/core/rendering/HitTestResult.h"
#include "sky/engine/core/rendering/RenderFlexibleBox.h"
#include "sky/engine/core/rendering/RenderGeometryMap.h"
#include "sky/engine/core/rendering/RenderInline.h"
#include "sky/engine/core/rendering/RenderLayer.h"
#include "sky/engine/core/rendering/RenderObjectInlines.h"
#include "sky/engine/core/rendering/RenderParagraph.h"
#include "sky/engine/core/rendering/RenderText.h"
#include "sky/engine/core/rendering/RenderTheme.h"
#include "sky/engine/core/rendering/RenderView.h"
#include "sky/engine/core/rendering/style/ShadowList.h"
#include "sky/engine/platform/JSONValues.h"
#include "sky/engine/platform/Partitions.h"
#include "sky/engine/platform/TraceEvent.h"
#include "sky/engine/platform/geometry/TransformState.h"
#include "sky/engine/platform/graphics/GraphicsContext.h"
#include "sky/engine/wtf/RefCountedLeakCounter.h"
#include "sky/engine/wtf/text/StringBuilder.h"
#include "sky/engine/wtf/text/WTFString.h"
#ifndef NDEBUG
#include <stdio.h>
#endif

namespace blink {

#if ENABLE(ASSERT)

RenderObject::SetLayoutNeededForbiddenScope::SetLayoutNeededForbiddenScope(RenderObject& renderObject)
    : m_renderObject(renderObject)
    , m_preexistingForbidden(m_renderObject.isSetNeedsLayoutForbidden())
{
    m_renderObject.setNeedsLayoutIsForbidden(true);
}

RenderObject::SetLayoutNeededForbiddenScope::~SetLayoutNeededForbiddenScope()
{
    m_renderObject.setNeedsLayoutIsForbidden(m_preexistingForbidden);
}
#endif

struct SameSizeAsRenderObject {
    virtual ~SameSizeAsRenderObject() { } // Allocate vtable pointer.
    void* pointers[4];
#if ENABLE(ASSERT)
    unsigned m_debugBitfields : 2;
#if ENABLE(OILPAN)
    unsigned m_oilpanBitfields : 1;
#endif
#endif
    unsigned m_bitfields;
};

COMPILE_ASSERT(sizeof(RenderObject) == sizeof(SameSizeAsRenderObject), RenderObject_should_stay_small);

bool RenderObject::s_affectsParentBlock = false;

#if !ENABLE(OILPAN)
void* RenderObject::operator new(size_t sz)
{
    ASSERT(isMainThread());
    return partitionAlloc(Partitions::getRenderingPartition(), sz);
}

void RenderObject::operator delete(void* ptr)
{
    ASSERT(isMainThread());
    partitionFree(ptr);
}
#endif

DEFINE_DEBUG_ONLY_GLOBAL(WTF::RefCountedLeakCounter, renderObjectCounter, ("RenderObject"));
unsigned RenderObject::s_instanceCount = 0;

RenderObject::RenderObject()
    : m_style(nullptr)
    , m_parent(nullptr)
    , m_previous(nullptr)
    , m_next(nullptr)
#if ENABLE(ASSERT)
    , m_setNeedsLayoutForbidden(false)
#if ENABLE(OILPAN)
    , m_didCallDestroy(false)
#endif
#endif
{
#ifndef NDEBUG
    renderObjectCounter.increment();
#endif
    ++s_instanceCount;
}

RenderObject::~RenderObject()
{
#if ENABLE(OILPAN)
    ASSERT(m_didCallDestroy);
#endif
#ifndef NDEBUG
    renderObjectCounter.decrement();
#endif
    --s_instanceCount;
}

String RenderObject::debugName() const
{
    return renderName();
}

bool RenderObject::isDescendantOf(const RenderObject* obj) const
{
    for (const RenderObject* r = this; r; r = r->m_parent) {
        if (r == obj)
            return true;
    }
    return false;
}

void RenderObject::addChild(RenderObject* newChild, RenderObject* beforeChild)
{
    RenderObjectChildList* children = virtualChildren();
    ASSERT(children);
    children->insertChildNode(this, newChild, beforeChild);
}

void RenderObject::removeChild(RenderObject* oldChild)
{
    RenderObjectChildList* children = virtualChildren();
    ASSERT(children);
    if (!children)
        return;

    children->removeChildNode(this, oldChild);
}

RenderObject* RenderObject::nextInPreOrder() const
{
    if (RenderObject* o = slowFirstChild())
        return o;

    return nextInPreOrderAfterChildren();
}

RenderObject* RenderObject::nextInPreOrderAfterChildren() const
{
    RenderObject* o = nextSibling();
    if (!o) {
        o = parent();
        while (o && !o->nextSibling())
            o = o->parent();
        if (o)
            o = o->nextSibling();
    }

    return o;
}

RenderObject* RenderObject::nextInPreOrder(const RenderObject* stayWithin) const
{
    if (RenderObject* o = slowFirstChild())
        return o;

    return nextInPreOrderAfterChildren(stayWithin);
}

RenderObject* RenderObject::nextInPreOrderAfterChildren(const RenderObject* stayWithin) const
{
    if (this == stayWithin)
        return 0;

    const RenderObject* current = this;
    RenderObject* next = current->nextSibling();
    for (; !next; next = current->nextSibling()) {
        current = current->parent();
        if (!current || current == stayWithin)
            return 0;
    }
    return next;
}

RenderObject* RenderObject::previousInPreOrder() const
{
    if (RenderObject* o = previousSibling()) {
        while (RenderObject* lastChild = o->slowLastChild())
            o = lastChild;
        return o;
    }

    return parent();
}

RenderObject* RenderObject::previousInPreOrder(const RenderObject* stayWithin) const
{
    if (this == stayWithin)
        return 0;

    return previousInPreOrder();
}

RenderObject* RenderObject::childAt(unsigned index) const
{
    RenderObject* child = slowFirstChild();
    for (unsigned i = 0; child && i < index; i++)
        child = child->nextSibling();
    return child;
}

RenderObject* RenderObject::lastLeafChild() const
{
    RenderObject* r = slowLastChild();
    while (r) {
        RenderObject* n = 0;
        n = r->slowLastChild();
        if (!n)
            break;
        r = n;
    }
    return r;
}

static void addLayers(RenderObject* obj, RenderLayer* parentLayer, RenderObject*& newObject,
                      RenderLayer*& beforeChild)
{
    if (obj->hasLayer()) {
        if (!beforeChild && newObject) {
            // We need to figure out the layer that follows newObject. We only do
            // this the first time we find a child layer, and then we update the
            // pointer values for newObject and beforeChild used by everyone else.
            beforeChild = newObject->parent()->findNextLayer(parentLayer, newObject);
            newObject = 0;
        }
        parentLayer->addChild(toRenderBox(obj)->layer(), beforeChild);
        return;
    }

    for (RenderObject* curr = obj->slowFirstChild(); curr; curr = curr->nextSibling())
        addLayers(curr, parentLayer, newObject, beforeChild);
}

void RenderObject::addLayers(RenderLayer* parentLayer)
{
    if (!parentLayer)
        return;

    RenderObject* object = this;
    RenderLayer* beforeChild = 0;
    blink::addLayers(this, parentLayer, object, beforeChild);
}

void RenderObject::removeLayers(RenderLayer* parentLayer)
{
    if (!parentLayer)
        return;

    if (hasLayer()) {
        parentLayer->removeChild(toRenderBox(this)->layer());
        return;
    }

    for (RenderObject* curr = slowFirstChild(); curr; curr = curr->nextSibling())
        curr->removeLayers(parentLayer);
}

void RenderObject::moveLayers(RenderLayer* oldParent, RenderLayer* newParent)
{
    if (!newParent)
        return;

    if (hasLayer()) {
        RenderLayer* layer = toRenderBox(this)->layer();
        ASSERT(oldParent == layer->parent());
        if (oldParent)
            oldParent->removeChild(layer);
        newParent->addChild(layer);
        return;
    }

    for (RenderObject* curr = slowFirstChild(); curr; curr = curr->nextSibling())
        curr->moveLayers(oldParent, newParent);
}

RenderLayer* RenderObject::findNextLayer(RenderLayer* parentLayer, RenderObject* startPoint,
                                         bool checkParent)
{
    // Error check the parent layer passed in. If it's null, we can't find anything.
    if (!parentLayer)
        return 0;

    // Step 1: If our layer is a child of the desired parent, then return our layer.
    RenderLayer* ourLayer = hasLayer() ? toRenderBox(this)->layer() : 0;
    if (ourLayer && ourLayer->parent() == parentLayer)
        return ourLayer;

    // Step 2: If we don't have a layer, or our layer is the desired parent, then descend
    // into our siblings trying to find the next layer whose parent is the desired parent.
    if (!ourLayer || ourLayer == parentLayer) {
        for (RenderObject* curr = startPoint ? startPoint->nextSibling() : slowFirstChild();
             curr; curr = curr->nextSibling()) {
            RenderLayer* nextLayer = curr->findNextLayer(parentLayer, 0, false);
            if (nextLayer)
                return nextLayer;
        }
    }

    // Step 3: If our layer is the desired parent layer, then we're finished. We didn't
    // find anything.
    if (parentLayer == ourLayer)
        return 0;

    // Step 4: If |checkParent| is set, climb up to our parent and check its siblings that
    // follow us to see if we can locate a layer.
    if (checkParent && parent())
        return parent()->findNextLayer(parentLayer, this, true);

    return 0;
}

RenderLayer* RenderObject::enclosingLayer() const
{
    for (const RenderObject* current = this; current; current = current->parent()) {
        if (current->hasLayer())
            return toRenderBox(current)->layer();
    }
    // FIXME: We should remove the one caller that triggers this case and make
    // this function return a reference.
    ASSERT(!m_parent && !isRenderView());
    return 0;
}

RenderBox* RenderObject::enclosingBox() const
{
    RenderObject* curr = const_cast<RenderObject*>(this);
    while (curr) {
        if (curr->isBox())
            return toRenderBox(curr);
        curr = curr->parent();
    }

    ASSERT_NOT_REACHED();
    return 0;
}

RenderBoxModelObject* RenderObject::enclosingBoxModelObject() const
{
    RenderObject* curr = const_cast<RenderObject*>(this);
    while (curr) {
        if (curr->isBoxModelObject())
            return toRenderBoxModelObject(curr);
        curr = curr->parent();
    }

    ASSERT_NOT_REACHED();
    return 0;
}

bool RenderObject::skipInvalidationWhenLaidOutChildren() const
{
    if (!neededLayoutBecauseOfChildren())
        return false;

    // SVG renderers need to be invalidated when their children are laid out.
    // RenderBlocks with line boxes are responsible to invalidate them so we can't ignore them.
    if (isRenderParagraph() && toRenderParagraph(this)->firstLineBox())
        return false;

    return rendererHasNoBoxEffect();
}

RenderBlock* RenderObject::firstLineBlock() const
{
    return 0;
}

static inline bool objectIsRelayoutBoundary(const RenderObject* object)
{
    if (!object->hasOverflowClip())
        return false;

    if (object->style()->width().isIntrinsicOrAuto() || object->style()->height().isIntrinsicOrAuto() || object->style()->height().isPercent())
        return false;

    return true;
}

void RenderObject::markContainingBlocksForLayout(bool scheduleRelayout, RenderObject* newRoot, SubtreeLayoutScope* layouter)
{
    ASSERT(!scheduleRelayout || !newRoot);
    ASSERT(!isSetNeedsLayoutForbidden());
    ASSERT(!layouter || this != layouter->root());

    RenderObject* object = container();
    RenderObject* last = this;

    bool simplifiedNormalFlowLayout = needsSimplifiedNormalFlowLayout() && !selfNeedsLayout() && !normalChildNeedsLayout();

    while (object) {
        if (object->selfNeedsLayout())
            return;

        // Don't mark the outermost object of an unrooted subtree. That object will be
        // marked when the subtree is added to the document.
        RenderObject* container = object->container();
        if (!container && !object->isRenderView())
            return;
        if (!last->isText() && last->style()->hasOutOfFlowPosition()) {
            bool willSkipRelativelyPositionedInlines = !object->isRenderBlock();
            // Skip relatively positioned inlines and anonymous blocks to get to the enclosing RenderBlock.
            while (object && !object->isRenderBlock())
                object = object->container();
            if (!object || object->posChildNeedsLayout())
                return;
            if (willSkipRelativelyPositionedInlines)
                container = object->container();
            object->setPosChildNeedsLayout(true);
            simplifiedNormalFlowLayout = true;
            ASSERT(!object->isSetNeedsLayoutForbidden());
        } else if (simplifiedNormalFlowLayout) {
            if (object->needsSimplifiedNormalFlowLayout())
                return;
            object->setNeedsSimplifiedNormalFlowLayout(true);
            ASSERT(!object->isSetNeedsLayoutForbidden());
        } else {
            if (object->normalChildNeedsLayout())
                return;
            object->setNormalChildNeedsLayout(true);
            ASSERT(!object->isSetNeedsLayoutForbidden());
        }

        if (layouter) {
            layouter->addRendererToLayout(object);
            if (object == layouter->root())
                return;
        }

        if (object == newRoot)
            return;

        last = object;
        if (scheduleRelayout && objectIsRelayoutBoundary(last))
            break;
        object = container;
    }

    if (scheduleRelayout)
        last->scheduleRelayout();
}

#if ENABLE(ASSERT)
void RenderObject::checkBlockPositionedObjectsNeedLayout()
{
    ASSERT(!needsLayout());

    if (isRenderBlock())
        toRenderBlock(this)->checkPositionedObjectsNeedLayout();
}
#endif

void RenderObject::setPreferredLogicalWidthsDirty(MarkingBehavior markParents)
{
    m_bitfields.setPreferredLogicalWidthsDirty(true);
    if (markParents == MarkContainingBlockChain && (isText() || !style()->hasOutOfFlowPosition()))
        invalidateContainerPreferredLogicalWidths();
}

void RenderObject::clearPreferredLogicalWidthsDirty()
{
    m_bitfields.setPreferredLogicalWidthsDirty(false);
}

void RenderObject::invalidateContainerPreferredLogicalWidths()
{
    // In order to avoid pathological behavior when inlines are deeply nested, we do include them
    // in the chain that we mark dirty (even though they're kind of irrelevant).
    RenderObject* o = container();
    while (o && !o->preferredLogicalWidthsDirty()) {
        // Don't invalidate the outermost object of an unrooted subtree. That object will be
        // invalidated when the subtree is added to the document.
        RenderObject* container = o->container();
        if (!container && !o->isRenderView())
            break;

        o->m_bitfields.setPreferredLogicalWidthsDirty(true);
        if (o->style()->hasOutOfFlowPosition())
            // A positioned object has no effect on the min/max width of its containing block ever.
            // We can optimize this case and not go up any further.
            break;
        o = container;
    }
}

RenderBlock* RenderObject::containingBlock() const
{
    RenderObject* o = parent();
    if (!isText() && m_style->position() == AbsolutePosition) {
        while (o) {
            // For relpositioned inlines, we return the nearest non-anonymous enclosing block. We don't try
            // to return the inline itself.  This allows us to avoid having a positioned objects
            // list in all RenderInlines and lets us return a strongly-typed RenderBlock* result
            // from this method.  The container() method can actually be used to obtain the
            // inline directly.
            if (o->style()->position() != StaticPosition && (!o->isInline() || o->isReplaced()))
                break;

            if (o->canContainAbsolutePositionObjects())
                break;

            if (o->style()->hasInFlowPosition() && o->isInline() && !o->isReplaced()) {
                o = o->containingBlock();
                break;
            }

            o = o->parent();
        }

        if (o && !o->isRenderBlock())
            o = o->containingBlock();
    } else {
        while (o && ((o->isInline() && !o->isReplaced()) || !o->isRenderBlock()))
            o = o->parent();
    }

    if (!o || !o->isRenderBlock())
        return 0; // This can still happen in case of an orphaned tree

    return toRenderBlock(o);
}

void RenderObject::drawLineForBoxSide(GraphicsContext* graphicsContext, int x1, int y1, int x2, int y2,
                                      BoxSide side, Color color, EBorderStyle style,
                                      int adjacentWidth1, int adjacentWidth2, bool antialias)
{
    int thickness;
    int length;
    if (side == BSTop || side == BSBottom) {
        thickness = y2 - y1;
        length = x2 - x1;
    } else {
        thickness = x2 - x1;
        length = y2 - y1;
    }

    // FIXME: We really would like this check to be an ASSERT as we don't want to draw empty borders. However
    // nothing guarantees that the following recursive calls to drawLineForBoxSide will have non-null dimensions.
    if (!thickness || !length)
        return;

    if (style == DOUBLE && thickness < 3)
        style = SOLID;

    switch (style) {
    case BNONE:
    case BHIDDEN:
        return;
    case DOTTED:
    case DASHED:
        drawDashedOrDottedBoxSide(graphicsContext, x1, y1, x2, y2, side,
            color, thickness, style, antialias);
        break;
    case DOUBLE:
        drawDoubleBoxSide(graphicsContext, x1, y1, x2, y2, length, side, color,
            thickness, adjacentWidth1, adjacentWidth2, antialias);
        break;
    case RIDGE:
    case GROOVE:
        drawRidgeOrGrooveBoxSide(graphicsContext, x1, y1, x2, y2, side, color,
            style, adjacentWidth1, adjacentWidth2, antialias);
        break;
    case INSET:
        // FIXME: Maybe we should lighten the colors on one side like Firefox.
        // https://bugs.webkit.org/show_bug.cgi?id=58608
        if (side == BSTop || side == BSLeft)
            color = color.dark();
        // fall through
    case OUTSET:
        if (style == OUTSET && (side == BSBottom || side == BSRight))
            color = color.dark();
        // fall through
    case SOLID:
        drawSolidBoxSide(graphicsContext, x1, y1, x2, y2, side, color, adjacentWidth1, adjacentWidth2, antialias);
        break;
    }
}

void RenderObject::drawDashedOrDottedBoxSide(GraphicsContext* graphicsContext, int x1, int y1, int x2, int y2,
    BoxSide side, Color color, int thickness, EBorderStyle style, bool antialias)
{
    if (thickness <= 0)
        return;

    bool wasAntialiased = graphicsContext->shouldAntialias();
    StrokeStyle oldStrokeStyle = graphicsContext->strokeStyle();
    graphicsContext->setShouldAntialias(antialias);
    graphicsContext->setStrokeColor(color);
    graphicsContext->setStrokeThickness(thickness);
    graphicsContext->setStrokeStyle(style == DASHED ? DashedStroke : DottedStroke);

    switch (side) {
    case BSBottom:
    case BSTop:
        graphicsContext->drawLine(IntPoint(x1, (y1 + y2) / 2), IntPoint(x2, (y1 + y2) / 2));
        break;
    case BSRight:
    case BSLeft:
        graphicsContext->drawLine(IntPoint((x1 + x2) / 2, y1), IntPoint((x1 + x2) / 2, y2));
        break;
    }
    graphicsContext->setShouldAntialias(wasAntialiased);
    graphicsContext->setStrokeStyle(oldStrokeStyle);
}

void RenderObject::drawDoubleBoxSide(GraphicsContext* graphicsContext, int x1, int y1, int x2, int y2,
    int length, BoxSide side, Color color, int thickness, int adjacentWidth1, int adjacentWidth2, bool antialias)
{
    int thirdOfThickness = (thickness + 1) / 3;
    ASSERT(thirdOfThickness);

    if (!adjacentWidth1 && !adjacentWidth2) {
        StrokeStyle oldStrokeStyle = graphicsContext->strokeStyle();
        graphicsContext->setStrokeStyle(NoStroke);
        graphicsContext->setFillColor(color);

        bool wasAntialiased = graphicsContext->shouldAntialias();
        graphicsContext->setShouldAntialias(antialias);

        switch (side) {
        case BSTop:
        case BSBottom:
            graphicsContext->drawRect(IntRect(x1, y1, length, thirdOfThickness));
            graphicsContext->drawRect(IntRect(x1, y2 - thirdOfThickness, length, thirdOfThickness));
            break;
        case BSLeft:
        case BSRight:
            // FIXME: Why do we offset the border by 1 in this case but not the other one?
            if (length > 1) {
                graphicsContext->drawRect(IntRect(x1, y1 + 1, thirdOfThickness, length - 1));
                graphicsContext->drawRect(IntRect(x2 - thirdOfThickness, y1 + 1, thirdOfThickness, length - 1));
            }
            break;
        }

        graphicsContext->setShouldAntialias(wasAntialiased);
        graphicsContext->setStrokeStyle(oldStrokeStyle);
        return;
    }

    int adjacent1BigThird = ((adjacentWidth1 > 0) ? adjacentWidth1 + 1 : adjacentWidth1 - 1) / 3;
    int adjacent2BigThird = ((adjacentWidth2 > 0) ? adjacentWidth2 + 1 : adjacentWidth2 - 1) / 3;

    switch (side) {
    case BSTop:
        drawLineForBoxSide(graphicsContext, x1 + std::max((-adjacentWidth1 * 2 + 1) / 3, 0),
            y1, x2 - std::max((-adjacentWidth2 * 2 + 1) / 3, 0), y1 + thirdOfThickness,
            side, color, SOLID, adjacent1BigThird, adjacent2BigThird, antialias);
        drawLineForBoxSide(graphicsContext, x1 + std::max((adjacentWidth1 * 2 + 1) / 3, 0),
            y2 - thirdOfThickness, x2 - std::max((adjacentWidth2 * 2 + 1) / 3, 0), y2,
            side, color, SOLID, adjacent1BigThird, adjacent2BigThird, antialias);
        break;
    case BSLeft:
        drawLineForBoxSide(graphicsContext, x1, y1 + std::max((-adjacentWidth1 * 2 + 1) / 3, 0),
            x1 + thirdOfThickness, y2 - std::max((-adjacentWidth2 * 2 + 1) / 3, 0),
            side, color, SOLID, adjacent1BigThird, adjacent2BigThird, antialias);
        drawLineForBoxSide(graphicsContext, x2 - thirdOfThickness, y1 + std::max((adjacentWidth1 * 2 + 1) / 3, 0),
            x2, y2 - std::max((adjacentWidth2 * 2 + 1) / 3, 0),
            side, color, SOLID, adjacent1BigThird, adjacent2BigThird, antialias);
        break;
    case BSBottom:
        drawLineForBoxSide(graphicsContext, x1 + std::max((adjacentWidth1 * 2 + 1) / 3, 0),
            y1, x2 - std::max((adjacentWidth2 * 2 + 1) / 3, 0), y1 + thirdOfThickness,
            side, color, SOLID, adjacent1BigThird, adjacent2BigThird, antialias);
        drawLineForBoxSide(graphicsContext, x1 + std::max((-adjacentWidth1 * 2 + 1) / 3, 0),
            y2 - thirdOfThickness, x2 - std::max((-adjacentWidth2 * 2 + 1) / 3, 0), y2,
            side, color, SOLID, adjacent1BigThird, adjacent2BigThird, antialias);
        break;
    case BSRight:
        drawLineForBoxSide(graphicsContext, x1, y1 + std::max((adjacentWidth1 * 2 + 1) / 3, 0),
            x1 + thirdOfThickness, y2 - std::max((adjacentWidth2 * 2 + 1) / 3, 0),
            side, color, SOLID, adjacent1BigThird, adjacent2BigThird, antialias);
        drawLineForBoxSide(graphicsContext, x2 - thirdOfThickness, y1 + std::max((-adjacentWidth1 * 2 + 1) / 3, 0),
            x2, y2 - std::max((-adjacentWidth2 * 2 + 1) / 3, 0),
            side, color, SOLID, adjacent1BigThird, adjacent2BigThird, antialias);
        break;
    default:
        break;
    }
}

void RenderObject::drawRidgeOrGrooveBoxSide(GraphicsContext* graphicsContext, int x1, int y1, int x2, int y2,
    BoxSide side, Color color, EBorderStyle style, int adjacentWidth1, int adjacentWidth2, bool antialias)
{
    EBorderStyle s1;
    EBorderStyle s2;
    if (style == GROOVE) {
        s1 = INSET;
        s2 = OUTSET;
    } else {
        s1 = OUTSET;
        s2 = INSET;
    }

    int adjacent1BigHalf = ((adjacentWidth1 > 0) ? adjacentWidth1 + 1 : adjacentWidth1 - 1) / 2;
    int adjacent2BigHalf = ((adjacentWidth2 > 0) ? adjacentWidth2 + 1 : adjacentWidth2 - 1) / 2;

    switch (side) {
    case BSTop:
        drawLineForBoxSide(graphicsContext, x1 + std::max(-adjacentWidth1, 0) / 2, y1, x2 - std::max(-adjacentWidth2, 0) / 2, (y1 + y2 + 1) / 2,
            side, color, s1, adjacent1BigHalf, adjacent2BigHalf, antialias);
        drawLineForBoxSide(graphicsContext, x1 + std::max(adjacentWidth1 + 1, 0) / 2, (y1 + y2 + 1) / 2, x2 - std::max(adjacentWidth2 + 1, 0) / 2, y2,
            side, color, s2, adjacentWidth1 / 2, adjacentWidth2 / 2, antialias);
        break;
    case BSLeft:
        drawLineForBoxSide(graphicsContext, x1, y1 + std::max(-adjacentWidth1, 0) / 2, (x1 + x2 + 1) / 2, y2 - std::max(-adjacentWidth2, 0) / 2,
            side, color, s1, adjacent1BigHalf, adjacent2BigHalf, antialias);
        drawLineForBoxSide(graphicsContext, (x1 + x2 + 1) / 2, y1 + std::max(adjacentWidth1 + 1, 0) / 2, x2, y2 - std::max(adjacentWidth2 + 1, 0) / 2,
            side, color, s2, adjacentWidth1 / 2, adjacentWidth2 / 2, antialias);
        break;
    case BSBottom:
        drawLineForBoxSide(graphicsContext, x1 + std::max(adjacentWidth1, 0) / 2, y1, x2 - std::max(adjacentWidth2, 0) / 2, (y1 + y2 + 1) / 2,
            side, color, s2, adjacent1BigHalf, adjacent2BigHalf, antialias);
        drawLineForBoxSide(graphicsContext, x1 + std::max(-adjacentWidth1 + 1, 0) / 2, (y1 + y2 + 1) / 2, x2 - std::max(-adjacentWidth2 + 1, 0) / 2, y2,
            side, color, s1, adjacentWidth1 / 2, adjacentWidth2 / 2, antialias);
        break;
    case BSRight:
        drawLineForBoxSide(graphicsContext, x1, y1 + std::max(adjacentWidth1, 0) / 2, (x1 + x2 + 1) / 2, y2 - std::max(adjacentWidth2, 0) / 2,
            side, color, s2, adjacent1BigHalf, adjacent2BigHalf, antialias);
        drawLineForBoxSide(graphicsContext, (x1 + x2 + 1) / 2, y1 + std::max(-adjacentWidth1 + 1, 0) / 2, x2, y2 - std::max(-adjacentWidth2 + 1, 0) / 2,
            side, color, s1, adjacentWidth1 / 2, adjacentWidth2 / 2, antialias);
        break;
    }
}

void RenderObject::drawSolidBoxSide(GraphicsContext* graphicsContext, int x1, int y1, int x2, int y2,
    BoxSide side, Color color, int adjacentWidth1, int adjacentWidth2, bool antialias)
{
    StrokeStyle oldStrokeStyle = graphicsContext->strokeStyle();
    graphicsContext->setStrokeStyle(NoStroke);
    graphicsContext->setFillColor(color);
    ASSERT(x2 >= x1);
    ASSERT(y2 >= y1);
    if (!adjacentWidth1 && !adjacentWidth2) {
        // Turn off antialiasing to match the behavior of drawConvexPolygon();
        // this matters for rects in transformed contexts.
        bool wasAntialiased = graphicsContext->shouldAntialias();
        graphicsContext->setShouldAntialias(antialias);
        graphicsContext->drawRect(IntRect(x1, y1, x2 - x1, y2 - y1));
        graphicsContext->setShouldAntialias(wasAntialiased);
        graphicsContext->setStrokeStyle(oldStrokeStyle);
        return;
    }
    FloatPoint quad[4];
    switch (side) {
    case BSTop:
        quad[0] = FloatPoint(x1 + std::max(-adjacentWidth1, 0), y1);
        quad[1] = FloatPoint(x1 + std::max(adjacentWidth1, 0), y2);
        quad[2] = FloatPoint(x2 - std::max(adjacentWidth2, 0), y2);
        quad[3] = FloatPoint(x2 - std::max(-adjacentWidth2, 0), y1);
        break;
    case BSBottom:
        quad[0] = FloatPoint(x1 + std::max(adjacentWidth1, 0), y1);
        quad[1] = FloatPoint(x1 + std::max(-adjacentWidth1, 0), y2);
        quad[2] = FloatPoint(x2 - std::max(-adjacentWidth2, 0), y2);
        quad[3] = FloatPoint(x2 - std::max(adjacentWidth2, 0), y1);
        break;
    case BSLeft:
        quad[0] = FloatPoint(x1, y1 + std::max(-adjacentWidth1, 0));
        quad[1] = FloatPoint(x1, y2 - std::max(-adjacentWidth2, 0));
        quad[2] = FloatPoint(x2, y2 - std::max(adjacentWidth2, 0));
        quad[3] = FloatPoint(x2, y1 + std::max(adjacentWidth1, 0));
        break;
    case BSRight:
        quad[0] = FloatPoint(x1, y1 + std::max(adjacentWidth1, 0));
        quad[1] = FloatPoint(x1, y2 - std::max(adjacentWidth2, 0));
        quad[2] = FloatPoint(x2, y2 - std::max(-adjacentWidth2, 0));
        quad[3] = FloatPoint(x2, y1 + std::max(-adjacentWidth1, 0));
        break;
    }

    graphicsContext->drawConvexPolygon(4, quad, antialias);
    graphicsContext->setStrokeStyle(oldStrokeStyle);
}

void RenderObject::addChildFocusRingRects(Vector<IntRect>& rects, const LayoutPoint& additionalOffset, const RenderBox* paintContainer) const
{
    for (RenderObject* current = slowFirstChild(); current; current = current->nextSibling()) {
        if (current->isText())
            continue;

        if (current->isBox()) {
            RenderBox* box = toRenderBox(current);
            if (box->hasLayer()) {
                Vector<IntRect> layerFocusRingRects;
                box->addFocusRingRects(layerFocusRingRects, LayoutPoint(), box);
                for (size_t i = 0; i < layerFocusRingRects.size(); ++i) {
                    FloatQuad quadInBox = box->localToContainerQuad(FloatRect(layerFocusRingRects[i]), paintContainer);
                    FloatRect rect = quadInBox.boundingBox();
                    // Floor the location instead of using pixelSnappedIntRect to match the !hasLayer() path.
                    // FIXME: roundedIntSize matches pixelSnappedIntRect in other places of addFocusRingRects
                    // because we always floor the offset.
                    // This assumption is fragile and should be replaced by better solution.
                    rects.append(IntRect(flooredIntPoint(rect.location()), roundedIntSize(rect.size())));
                }
            } else {
                FloatPoint pos(additionalOffset);
                pos.move(box->locationOffset());
                box->addFocusRingRects(rects, flooredIntPoint(pos), paintContainer);
            }
        } else {
            current->addFocusRingRects(rects, additionalOffset, paintContainer);
        }
    }
}

IntRect RenderObject::absoluteBoundingBoxRect() const
{
    Vector<FloatQuad> quads;
    absoluteQuads(quads);

    size_t n = quads.size();
    if (!n)
        return IntRect();

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

void RenderObject::addAbsoluteRectForLayer(LayoutRect& result)
{
    if (hasLayer())
        result.unite(absoluteBoundingBoxRect());
    for (RenderObject* current = slowFirstChild(); current; current = current->nextSibling())
        current->addAbsoluteRectForLayer(result);
}

void RenderObject::paint(PaintInfo&, const LayoutPoint&, Vector<RenderBox*>& layers)
{
}

void RenderObject::dirtyLinesFromChangedChild(RenderObject*)
{
}

#ifndef NDEBUG

void RenderObject::showTreeForThis() const
{
}

void RenderObject::showRenderTreeForThis() const
{
    showRenderTree(this, 0);
}

void RenderObject::showLineTreeForThis() const
{
    if (containingBlock())
        containingBlock()->showLineTreeAndMark(0, 0, 0, 0, this);
}

void RenderObject::showRenderObject() const
{
    showRenderObject(0);
}

void RenderObject::showRenderObject(int printedCharacters) const
{
    printedCharacters += fprintf(stderr, "%s %p", renderName(), this);
    fputc('\n', stderr);
}

void RenderObject::showRenderTreeAndMark(const RenderObject* markedObject1, const char* markedLabel1, const RenderObject* markedObject2, const char* markedLabel2, int depth) const
{
    int printedCharacters = 0;
    if (markedObject1 == this && markedLabel1)
        printedCharacters += fprintf(stderr, "%s", markedLabel1);
    if (markedObject2 == this && markedLabel2)
        printedCharacters += fprintf(stderr, "%s", markedLabel2);
    for (; printedCharacters < depth * 2; printedCharacters++)
        fputc(' ', stderr);

    showRenderObject(printedCharacters);

    for (const RenderObject* child = slowFirstChild(); child; child = child->nextSibling())
        child->showRenderTreeAndMark(markedObject1, markedLabel1, markedObject2, markedLabel2, depth + 1);
}

#endif // NDEBUG

bool RenderObject::isSelectable() const
{
    return !(style()->userSelect() == SELECT_NONE && style()->userModify() == READ_ONLY);
}

Color RenderObject::selectionBackgroundColor() const
{
    ASSERT_NOT_REACHED();
    // TODO(ianh): if we expose selection painting, we should expose a way to set the background colour
    // TODO(ianh): need to be able to configure whether to consider the selection focused and active or not
    if (!isSelectable())
        return Color::transparent;
    bool isFocusedAndActive = true;
    return isFocusedAndActive ?
        RenderTheme::theme().activeSelectionBackgroundColor() :
        RenderTheme::theme().inactiveSelectionBackgroundColor();
}

Color RenderObject::selectionColor() const
{
    ASSERT_NOT_REACHED();
    return style()->color();
}

Color RenderObject::selectionForegroundColor() const
{
    return selectionColor();
}

Color RenderObject::selectionEmphasisMarkColor() const
{
    return selectionColor();
}

void RenderObject::selectionStartEnd(int& spos, int& epos) const
{
    spos = -1;
    epos = -1;
}

StyleDifference RenderObject::adjustStyleDifference(StyleDifference diff) const
{
    // The answer to layerTypeRequired() for plugins, iframes, and canvas can change without the actual
    // style changing, since it depends on whether we decide to composite these elements. When the
    // layer status of one of these elements changes, we need to force a layout.
    if (!diff.needsFullLayout() && style() && isBox()) {
        bool requiresLayer = toRenderBox(this)->layerTypeRequired() != NoLayer;
        if (hasLayer() != requiresLayer)
            diff.setNeedsFullLayout();
    }

    return diff;
}

inline bool RenderObject::hasImmediateNonWhitespaceTextChildOrPropertiesDependentOnColor() const
{
    if (style()->hasBorder() || style()->hasOutline())
        return true;
    for (const RenderObject* r = slowFirstChild(); r; r = r->nextSibling()) {
        if (r->isText() && !toRenderText(r)->isAllCollapsibleWhitespace())
            return true;
        if (r->style()->hasOutline() || r->style()->hasBorder())
            return true;
    }
    return false;
}

void RenderObject::markContainingBlocksForOverflowRecalc()
{
    for (RenderBlock* container = containingBlock(); container && !container->childNeedsOverflowRecalcAfterStyleChange(); container = container->containingBlock())
        container->setChildNeedsOverflowRecalcAfterStyleChange(true);
}

void RenderObject::setNeedsOverflowRecalcAfterStyleChange()
{
    bool neededRecalc = needsOverflowRecalcAfterStyleChange();
    setSelfNeedsOverflowRecalcAfterStyleChange(true);
    if (!neededRecalc)
        markContainingBlocksForOverflowRecalc();
}

void RenderObject::setStyle(PassRefPtr<RenderStyle> style)
{
    ASSERT(style);
    StyleDifference diff;
    if (m_style)
        diff = m_style->visualInvalidationDiff(*style);

    diff = adjustStyleDifference(diff);

    styleWillChange(diff, *style);

    RefPtr<RenderStyle> oldStyle = m_style.release();
    setStyleInternal(style);

    updateFillImages(oldStyle ? &oldStyle->backgroundLayers() : 0, m_style->backgroundLayers());

    bool doesNotNeedLayout = !m_parent || isText();

    styleDidChange(diff, oldStyle.get());

    // FIXME: |this| might be destroyed here. This can currently happen for a RenderTextFragment when
    // its first-letter block gets an update in RenderTextFragment::styleDidChange. For RenderTextFragment(s),
    // we will safely bail out with the doesNotNeedLayout flag. We might want to broaden this condition
    // in the future as we move renderer changes out of layout and into style changes.
    // FIXME(sky): Remove this.
    if (doesNotNeedLayout)
        return;

    // Now that the layer (if any) has been updated, we need to adjust the diff again,
    // check whether we should layout now, and decide if we need to invalidate paints.
    StyleDifference updatedDiff = adjustStyleDifference(diff);

    if (!diff.needsFullLayout()) {
        if (updatedDiff.needsFullLayout())
            setNeedsLayoutAndPrefWidthsRecalc();
        else if (updatedDiff.needsPositionedMovementLayout())
            setNeedsPositionedMovementLayout();
    }

    if (diff.transformChanged() && !needsLayout()) {
        if (RenderBlock* container = containingBlock())
            container->setNeedsOverflowRecalcAfterStyleChange();
    }
}

void RenderObject::styleWillChange(StyleDifference diff, const RenderStyle& newStyle)
{
    if (m_style) {
        if (isOutOfFlowPositioned() && (m_style->position() != newStyle.position()))
            // For changes in positioning styles, we need to conceivably remove ourselves
            // from the positioned objects list.
            toRenderBox(this)->removeFloatingOrPositionedChildFromBlockLists();

        s_affectsParentBlock = isFloatingOrOutOfFlowPositioned()
            && !newStyle.hasOutOfFlowPosition()
            && parent() && (parent()->isRenderParagraph() || parent()->isRenderInline());

        // Clearing these bits is required to avoid leaving stale renderers.
        // FIXME: We shouldn't need that hack if our logic was totally correct.
        if (diff.needsLayout()) {
            clearPositionedState();
        }
    } else {
        s_affectsParentBlock = false;
    }
}

void RenderObject::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
    if (s_affectsParentBlock) {
        // An object that was floating or positioned became a normal flow object again.  We have to make sure the
        // render tree updates as needed to accommodate the new normal flow object.
        setInline(style()->isDisplayInlineType());
        ASSERT(isInline() == parent()->isRenderParagraph());
    }

    if (!m_parent)
        return;

    if (diff.needsFullLayout()) {
        // If the object already needs layout, then setNeedsLayout won't do
        // any work. But if the containing block has changed, then we may need
        // to mark the new containing blocks for layout. The change that can
        // directly affect the containing block of this object is a change to
        // the position style.
        if (needsLayout() && oldStyle->position() != m_style->position())
            markContainingBlocksForLayout();

        // Ditto.
        if (needsOverflowRecalcAfterStyleChange() && oldStyle->position() != m_style->position())
            markContainingBlocksForOverflowRecalc();

        if (diff.needsFullLayout())
            setNeedsLayoutAndPrefWidthsRecalc();
    } else if (diff.needsPositionedMovementLayout())
        setNeedsPositionedMovementLayout();

    // Don't check for paint invalidation here; we need to wait until the layer has been
    // updated by subclasses before we know if we have to invalidate paints (in setStyle()).
}

void RenderObject::updateFillImages(const FillLayer* oldLayers, const FillLayer& newLayers)
{
    // Optimize the common case
    if (oldLayers && !oldLayers->next() && !newLayers.next() && (oldLayers->image() == newLayers.image()))
        return;

    // Go through the new layers and addClients first, to avoid removing all clients of an image.
    for (const FillLayer* currNew = &newLayers; currNew; currNew = currNew->next()) {
        if (currNew->image())
            currNew->image()->addClient(this);
    }

    for (const FillLayer* currOld = oldLayers; currOld; currOld = currOld->next()) {
        if (currOld->image())
            currOld->image()->removeClient(this);
    }
}

void RenderObject::updateImage(StyleImage* oldImage, StyleImage* newImage)
{
    if (oldImage != newImage) {
        if (oldImage)
            oldImage->removeClient(this);
        if (newImage)
            newImage->addClient(this);
    }
}

FloatPoint RenderObject::localToAbsolute(const FloatPoint& localPoint, MapCoordinatesFlags mode) const
{
    TransformState transformState(TransformState::ApplyTransformDirection, localPoint);
    mapLocalToContainer(0, transformState, mode | ApplyContainerFlip);
    transformState.flatten();

    return transformState.lastPlanarPoint();
}

FloatPoint RenderObject::absoluteToLocal(const FloatPoint& containerPoint, MapCoordinatesFlags mode) const
{
    TransformState transformState(TransformState::UnapplyInverseTransformDirection, containerPoint);
    mapAbsoluteToLocalPoint(mode, transformState);
    transformState.flatten();

    return transformState.lastPlanarPoint();
}

FloatQuad RenderObject::absoluteToLocalQuad(const FloatQuad& quad, MapCoordinatesFlags mode) const
{
    TransformState transformState(TransformState::UnapplyInverseTransformDirection, quad.boundingBox().center(), quad);
    mapAbsoluteToLocalPoint(mode, transformState);
    transformState.flatten();
    return transformState.lastPlanarQuad();
}

void RenderObject::mapLocalToContainer(const RenderBox* paintInvalidationContainer, TransformState& transformState, MapCoordinatesFlags mode) const
{
    if (paintInvalidationContainer == this)
        return;

    RenderObject* o = parent();
    if (!o)
        return;

    // FIXME: this should call offsetFromContainer to share code, but I'm not sure it's ever called.
    if (mode & ApplyContainerFlip && o->isBox())
        mode &= ~ApplyContainerFlip;

    o->mapLocalToContainer(paintInvalidationContainer, transformState, mode);
}

const RenderObject* RenderObject::pushMappingToContainer(const RenderBox* ancestorToStopAt, RenderGeometryMap& geometryMap) const
{
    ASSERT_UNUSED(ancestorToStopAt, ancestorToStopAt != this);

    RenderObject* container = parent();
    if (!container)
        return 0;
    // FIXME(sky): Do we need to make this call?
    geometryMap.push(this, LayoutSize(), false);
    return container;
}

void RenderObject::mapAbsoluteToLocalPoint(MapCoordinatesFlags mode, TransformState& transformState) const
{
    RenderObject* o = parent();
    if (o)
        o->mapAbsoluteToLocalPoint(mode, transformState);
}

bool RenderObject::shouldUseTransformFromContainer(const RenderObject* containerObject) const
{
    // hasTransform() indicates whether the object has transform, transform-style or perspective. We just care about transform,
    // so check the layer's transform directly.
    return (isBox() && toRenderBox(this)->transform()) || (containerObject && containerObject->style()->hasPerspective());
}

void RenderObject::getTransformFromContainer(const RenderObject* containerObject, const LayoutSize& offsetInContainer, TransformationMatrix& transform) const
{
    transform.makeIdentity();
    transform.translate(offsetInContainer.width().toFloat(), offsetInContainer.height().toFloat());
    TransformationMatrix* localTransform = isBox() ? toRenderBox(this)->transform() : 0;
    if (localTransform)
        transform.multiply(*localTransform);

    if (containerObject && containerObject->hasLayer() && containerObject->style()->hasPerspective()) {
        // Perpsective on the container affects us, so we have to factor it in here.
        ASSERT(containerObject->hasLayer());
        FloatPoint perspectiveOrigin = toRenderBox(containerObject)->perspectiveOrigin();

        TransformationMatrix perspectiveMatrix;
        perspectiveMatrix.applyPerspective(containerObject->style()->perspective());

        transform.translateRight3d(-perspectiveOrigin.x(), -perspectiveOrigin.y(), 0);
        transform = perspectiveMatrix * transform;
        transform.translateRight3d(perspectiveOrigin.x(), perspectiveOrigin.y(), 0);
    }
}

FloatQuad RenderObject::localToContainerQuad(const FloatQuad& localQuad, const RenderBox* paintInvalidationContainer, MapCoordinatesFlags mode) const
{
    // Track the point at the center of the quad's bounding box. As mapLocalToContainer() calls offsetFromContainer(),
    // it will use that point as the reference point to decide which column's transform to apply in multiple-column blocks.
    TransformState transformState(TransformState::ApplyTransformDirection, localQuad.boundingBox().center(), localQuad);
    mapLocalToContainer(paintInvalidationContainer, transformState, mode | ApplyContainerFlip | UseTransforms);
    transformState.flatten();

    return transformState.lastPlanarQuad();
}

FloatPoint RenderObject::localToContainerPoint(const FloatPoint& localPoint, const RenderBox* paintInvalidationContainer, MapCoordinatesFlags mode) const
{
    TransformState transformState(TransformState::ApplyTransformDirection, localPoint);
    mapLocalToContainer(paintInvalidationContainer, transformState, mode | ApplyContainerFlip | UseTransforms);
    transformState.flatten();

    return transformState.lastPlanarPoint();
}

LayoutSize RenderObject::offsetFromContainer(const RenderObject* o, const LayoutPoint& point, bool* offsetDependsOnPoint) const
{
    ASSERT(o == container());
    LayoutSize offset;
    if (offsetDependsOnPoint)
        *offsetDependsOnPoint = false;
    return offset;
}

LayoutSize RenderObject::offsetFromAncestorContainer(const RenderObject* container) const
{
    LayoutSize offset;
    LayoutPoint referencePoint;
    const RenderObject* currContainer = this;
    do {
        const RenderObject* nextContainer = currContainer->container();
        ASSERT(nextContainer);  // This means we reached the top without finding container.
        if (!nextContainer)
            break;
        ASSERT(!currContainer->hasTransform());
        LayoutSize currentOffset = currContainer->offsetFromContainer(nextContainer, referencePoint);
        offset += currentOffset;
        referencePoint.move(currentOffset);
        currContainer = nextContainer;
    } while (currContainer != container);

    return offset;
}

LayoutRect RenderObject::localCaretRect(InlineBox*, int, LayoutUnit* extraWidthToEndOfLine)
{
    if (extraWidthToEndOfLine)
        *extraWidthToEndOfLine = 0;

    return LayoutRect();
}

bool RenderObject::isRooted() const
{
    const RenderObject* object = this;
    while (object->parent() && !object->hasLayer())
        object = object->parent();
    if (object->hasLayer())
        return toRenderBox(object)->layer()->root()->isRootLayer();
    return false;
}

RespectImageOrientationEnum RenderObject::shouldRespectImageOrientation() const
{
    return DoNotRespectImageOrientation;
}

bool RenderObject::hasEntirelyFixedBackground() const
{
    return m_style->hasEntirelyFixedBackground();
}

RenderObject* RenderObject::container(const RenderBox* paintInvalidationContainer, bool* paintInvalidationContainerSkipped) const
{
    if (paintInvalidationContainerSkipped)
        *paintInvalidationContainerSkipped = false;

    // This method is extremely similar to containingBlock(), but with a few notable
    // exceptions.
    // (1) It can be used on orphaned subtrees, i.e., it can be called safely even when
    // the object is not part of the primary document subtree yet.
    // (2) For normal flow elements, it just returns the parent.
    // (3) For absolute positioned elements, it will return a relative positioned inline.
    // containingBlock() simply skips relpositioned inlines and lets an enclosing block handle
    // the layout of the positioned object.  This does mean that computePositionedLogicalWidth and
    // computePositionedLogicalHeight have to use container().
    RenderObject* o = parent();

    if (isText())
        return o;

    EPosition pos = m_style->position();
    if (pos == AbsolutePosition) {
        // We technically just want our containing block, but
        // we may not have one if we're part of an uninstalled
        // subtree. We'll climb as high as we can though.
        while (o) {
            if (o->style()->position() != StaticPosition)
                break;

            if (o->canContainAbsolutePositionObjects())
                break;

            if (paintInvalidationContainerSkipped && o == paintInvalidationContainer)
                *paintInvalidationContainerSkipped = true;

            o = o->parent();
        }
    }

    return o;
}

bool RenderObject::isSelectionBorder() const
{
    SelectionState st = selectionState();
    return st == SelectionStart || st == SelectionEnd || st == SelectionBoth;
}

inline void RenderObject::clearLayoutRootIfNeeded() const
{
}

void RenderObject::willBeDestroyed()
{
    // Destroy any leftover anonymous children.
    RenderObjectChildList* children = virtualChildren();
    if (children)
        children->destroyLeftoverChildren();

    remove();
    setAncestorLineBoxDirty(false);
    clearLayoutRootIfNeeded();
}

void RenderObject::insertedIntoTree()
{
    // FIXME: We should ASSERT(isRooted()) here but generated content makes some out-of-order insertion.

    // Keep our layer hierarchy updated. Optimize for the common case where we don't have any children
    // and don't have a layer attached to ourselves.
    RenderLayer* layer = 0;
    if (slowFirstChild() || hasLayer()) {
        layer = parent()->enclosingLayer();
        addLayers(layer);
    }

    if (parent()->isRenderParagraph())
        parent()->dirtyLinesFromChangedChild(this);
}

void RenderObject::willBeRemovedFromTree()
{
    // FIXME: We should ASSERT(isRooted()) but we have some out-of-order removals which would need to be fixed first.

    // Keep our layer hierarchy updated.
    if (slowFirstChild() || hasLayer())
        removeLayers(parent()->enclosingLayer());

    if (isOutOfFlowPositioned() && parent()->isRenderParagraph())
        parent()->dirtyLinesFromChangedChild(this);
}

void RenderObject::destroy()
{
#if ENABLE(ASSERT) && ENABLE(OILPAN)
    ASSERT(!m_didCallDestroy);
    m_didCallDestroy = true;
#endif
    willBeDestroyed();
    postDestroy();
}

void RenderObject::postDestroy()
{
    // It seems ugly that this is not in willBeDestroyed().
    if (m_style) {
        for (const FillLayer* bgLayer = &m_style->backgroundLayers(); bgLayer; bgLayer = bgLayer->next()) {
            if (StyleImage* backgroundImage = bgLayer->image())
                backgroundImage->removeClient(this);
        }
    }
    delete this;
}

// FIXME(sky): Change the callers to use nodeAtPoint direclty and remove this function.
// Or, rename nodeAtPoint to hitTest?
bool RenderObject::hitTest(const HitTestRequest& request, HitTestResult& result, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset)
{
    return nodeAtPoint(request, result, locationInContainer, accumulatedOffset);
}

void RenderObject::updateHitTestResult(HitTestResult& result, const LayoutPoint& point)
{
}

bool RenderObject::nodeAtPoint(const HitTestRequest&, HitTestResult&, const HitTestLocation& /*locationInContainer*/, const LayoutPoint& /*accumulatedOffset*/)
{
    return false;
}

void RenderObject::scheduleRelayout()
{
}

void RenderObject::forceLayout()
{
    setSelfNeedsLayout(true);
    layout();
}

// FIXME: Does this do anything different than forceLayout given that we don't walk
// the containing block chain. If not, we should change all callers to use forceLayout.
void RenderObject::forceChildLayout()
{
    setNormalChildNeedsLayout(true);
    layout();
}

void RenderObject::getTextDecorations(unsigned decorations, AppliedTextDecoration& underline, AppliedTextDecoration& overline, AppliedTextDecoration& linethrough, bool quirksMode, bool firstlineStyle)
{
    RenderObject* curr = this;
    RenderStyle* styleToUse = 0;
    unsigned currDecs = TextDecorationNone;
    Color resultColor;
    TextDecorationStyle resultStyle;
    do {
        styleToUse = curr->style(firstlineStyle);
        currDecs = styleToUse->textDecoration();
        currDecs &= decorations;
        resultColor = styleToUse->decorationColor();
        resultStyle = styleToUse->textDecorationStyle();
        // Parameter 'decorations' is cast as an int to enable the bitwise operations below.
        if (currDecs) {
            if (currDecs & TextDecorationUnderline) {
                decorations &= ~TextDecorationUnderline;
                underline.color = resultColor;
                underline.style = resultStyle;
            }
            if (currDecs & TextDecorationOverline) {
                decorations &= ~TextDecorationOverline;
                overline.color = resultColor;
                overline.style = resultStyle;
            }
            if (currDecs & TextDecorationLineThrough) {
                decorations &= ~TextDecorationLineThrough;
                linethrough.color = resultColor;
                linethrough.style = resultStyle;
            }
        }
        curr = curr->parent();
    } while (curr && decorations);

    // If we bailed out, use the element we bailed out at (typically a <font> or <a> element).
    if (decorations && curr) {
        styleToUse = curr->style(firstlineStyle);
        resultColor = styleToUse->decorationColor();
        if (decorations & TextDecorationUnderline) {
            underline.color = resultColor;
            underline.style = resultStyle;
        }
        if (decorations & TextDecorationOverline) {
            overline.color = resultColor;
            overline.style = resultStyle;
        }
        if (decorations & TextDecorationLineThrough) {
            linethrough.color = resultColor;
            linethrough.style = resultStyle;
        }
    }
}

int RenderObject::caretMinOffset() const
{
    return 0;
}

int RenderObject::caretMaxOffset() const
{
    if (isReplaced())
        return 1;
    return 0;
}

int RenderObject::previousOffset(int current) const
{
    return current - 1;
}

int RenderObject::previousOffsetForBackwardDeletion(int current) const
{
    return current - 1;
}

int RenderObject::nextOffset(int current) const
{
    return current + 1;
}

// touch-action applies to all elements with both width AND height properties.
// According to the CSS Box Model Spec (http://dev.w3.org/csswg/css-box/#the-width-and-height-properties)
// width applies to all elements but non-replaced inline elements, table rows, and row groups and
// height applies to all elements but non-replaced inline elements, table columns, and column groups.
bool RenderObject::supportsTouchAction() const
{
    if (isInline() && !isReplaced())
        return false;
    return true;
}

bool RenderObject::canUpdateSelectionOnRootLineBoxes()
{
    if (needsLayout())
        return false;

    RenderBlock* containingBlock = this->containingBlock();
    return containingBlock ? !containingBlock->needsLayout() : false;
}

bool RenderObject::nodeAtFloatPoint(const HitTestRequest&, HitTestResult&, const FloatPoint&)
{
    ASSERT_NOT_REACHED();
    return false;
}

} // namespace blink

#ifndef NDEBUG

void showTree(const blink::RenderObject* object)
{
    if (object)
        object->showTreeForThis();
}

void showLineTree(const blink::RenderObject* object)
{
    if (object)
        object->showLineTreeForThis();
}

void showRenderTree(const blink::RenderObject* object1)
{
    showRenderTree(object1, 0);
}

void showRenderTree(const blink::RenderObject* object1, const blink::RenderObject* object2)
{
    if (object1) {
        const blink::RenderObject* root = object1;
        while (root->parent())
            root = root->parent();
        root->showRenderTreeAndMark(object1, "*", object2, "-", 0);
    }
}

#endif