Merge WebKit at r75315: Initial merge by git.

Change-Id: I570314b346ce101c935ed22a626b48c2af266b84

1 files changed, 523 insertions, 0 deletions

diff --git a/Source/WebCore/rendering/RenderBox.h b/Source/WebCore/rendering/RenderBox.h
new file mode 100644
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+++ b/Source/WebCore/rendering/RenderBox.h
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+/*
+ * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
+ *           (C) 1999 Antti Koivisto (koivisto@kde.org)
+ * Copyright (C) 2003, 2006, 2007 Apple Inc. All rights reserved.
+ *
+ * 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.
+ *
+ */
+
+#ifndef RenderBox_h
+#define RenderBox_h
+
+#include "RenderBoxModelObject.h"
+#include "RenderOverflow.h"
+#include "ScrollTypes.h"
+
+namespace WebCore {
+
+enum LogicalWidthType { LogicalWidth, MinLogicalWidth, MaxLogicalWidth };
+
+class RenderBox : public RenderBoxModelObject {
+public:
+    RenderBox(Node*);
+    virtual ~RenderBox();
+
+    // Use this with caution! No type checking is done!
+    RenderBox* firstChildBox() const;
+    RenderBox* lastChildBox() const;
+
+    int x() const { return m_frameRect.x(); }
+    int y() const { return m_frameRect.y(); }
+    int width() const { return m_frameRect.width(); }
+    int height() const { return m_frameRect.height(); }
+
+    void setX(int x) { m_frameRect.setX(x); }
+    void setY(int y) { m_frameRect.setY(y); }
+    void setWidth(int width) { m_frameRect.setWidth(width); }
+    void setHeight(int height) { m_frameRect.setHeight(height); }
+
+    int logicalLeft() const { return style()->isHorizontalWritingMode() ? x() : y(); }
+    int logicalRight() const { return logicalLeft() + logicalWidth(); }
+    int logicalTop() const { return style()->isHorizontalWritingMode() ? y() : x(); }
+    int logicalBottom() const { return logicalTop() + logicalHeight(); }
+    int logicalWidth() const { return style()->isHorizontalWritingMode() ? width() : height(); }
+    int logicalHeight() const { return style()->isHorizontalWritingMode() ? height() : width(); }
+
+    void setLogicalLeft(int left)
+    {
+        if (style()->isHorizontalWritingMode())
+            setX(left);
+        else
+            setY(left);
+    }
+    void setLogicalTop(int top)
+    {
+        if (style()->isHorizontalWritingMode())
+            setY(top);
+        else
+            setX(top);
+    }
+    void setLogicalWidth(int size)
+    {
+        if (style()->isHorizontalWritingMode())
+            setWidth(size);
+        else
+            setHeight(size);
+    }
+    void setLogicalHeight(int size)
+    {
+        if (style()->isHorizontalWritingMode())
+            setHeight(size);
+        else
+            setWidth(size);
+    }
+    void setLogicalLocation(int left, int top)
+    {
+        if (style()->isHorizontalWritingMode())
+            setLocation(left, top);
+        else
+            setLocation(top, left);
+    }
+
+    IntPoint location() const { return m_frameRect.location(); }
+    IntSize locationOffset() const { return IntSize(x(), y()); }
+    IntSize size() const { return m_frameRect.size(); }
+
+    void setLocation(const IntPoint& location) { m_frameRect.setLocation(location); }
+    void setLocation(int x, int y) { setLocation(IntPoint(x, y)); }
+    
+    void setSize(const IntSize& size) { m_frameRect.setSize(size); }
+    void move(int dx, int dy) { m_frameRect.move(dx, dy); }
+
+    IntRect frameRect() const { return m_frameRect; }
+    void setFrameRect(const IntRect& rect) { m_frameRect = rect; }
+
+    IntRect borderBoxRect() const { return IntRect(0, 0, width(), height()); }
+    virtual IntRect borderBoundingBox() const { return borderBoxRect(); } 
+
+    // The content area of the box (excludes padding and border).
+    IntRect contentBoxRect() const { return IntRect(borderLeft() + paddingLeft(), borderTop() + paddingTop(), contentWidth(), contentHeight()); }
+    // The content box in absolute coords. Ignores transforms.
+    IntRect absoluteContentBox() const;
+    // The content box converted to absolute coords (taking transforms into account).
+    FloatQuad absoluteContentQuad() const;
+
+    // Bounds of the outline box in absolute coords. Respects transforms
+    virtual IntRect outlineBoundsForRepaint(RenderBoxModelObject* /*repaintContainer*/, IntPoint* cachedOffsetToRepaintContainer) const;
+    virtual void addFocusRingRects(Vector<IntRect>&, int tx, int ty);
+
+    // Use this with caution! No type checking is done!
+    RenderBox* previousSiblingBox() const;
+    RenderBox* nextSiblingBox() const;
+    RenderBox* parentBox() const;
+
+    IntRect layoutOverflowRect() const { return m_overflow ? m_overflow->layoutOverflowRect() : clientBoxRect(); }
+    int topLayoutOverflow() const { return m_overflow? m_overflow->topLayoutOverflow() : borderTop(); }
+    int bottomLayoutOverflow() const { return m_overflow ? m_overflow->bottomLayoutOverflow() : borderTop() + clientHeight(); }
+    int leftLayoutOverflow() const { return m_overflow ? m_overflow->leftLayoutOverflow() : borderLeft(); }
+    int rightLayoutOverflow() const { return m_overflow ? m_overflow->rightLayoutOverflow() : borderLeft() + clientWidth(); }
+    int logicalLeftLayoutOverflow() const { return style()->isHorizontalWritingMode() ? leftLayoutOverflow() : topLayoutOverflow(); }
+    int logicalRightLayoutOverflow() const { return style()->isHorizontalWritingMode() ? rightLayoutOverflow() : bottomLayoutOverflow(); }
+    
+    IntRect visualOverflowRect() const { return m_overflow ? m_overflow->visualOverflowRect() : borderBoxRect(); }
+    int topVisualOverflow() const { return m_overflow? m_overflow->topVisualOverflow() : 0; }
+    int bottomVisualOverflow() const { return m_overflow ? m_overflow->bottomVisualOverflow() : height(); }
+    int leftVisualOverflow() const { return m_overflow ? m_overflow->leftVisualOverflow() : 0; }
+    int rightVisualOverflow() const { return m_overflow ? m_overflow->rightVisualOverflow() : width(); }
+    int logicalLeftVisualOverflow() const { return style()->isHorizontalWritingMode() ? leftVisualOverflow() : topVisualOverflow(); }
+    int logicalRightVisualOverflow() const { return style()->isHorizontalWritingMode() ? rightVisualOverflow() : bottomVisualOverflow(); }
+    
+    void addLayoutOverflow(const IntRect&);
+    void addVisualOverflow(const IntRect&);
+    
+    void addShadowOverflow();
+    void addOverflowFromChild(RenderBox* child) { addOverflowFromChild(child, IntSize(child->x(), child->y())); }
+    void addOverflowFromChild(RenderBox* child, const IntSize& delta);
+    void clearLayoutOverflow();
+    
+    void updateLayerTransform();
+
+    void blockDirectionOverflow(bool isLineHorizontal, int& logicalTopLayoutOverflow, int& logicalBottomLayoutOverflow,
+                                int& logicalTopVisualOverflow, int& logicalBottomVisualOverflow);
+
+    int contentWidth() const { return clientWidth() - paddingLeft() - paddingRight(); }
+    int contentHeight() const { return clientHeight() - paddingTop() - paddingBottom(); }
+    int contentLogicalWidth() const { return style()->isHorizontalWritingMode() ? contentWidth() : contentHeight(); }
+    int contentLogicalHeight() const { return style()->isHorizontalWritingMode() ? contentHeight() : contentWidth(); }
+
+    // IE extensions. Used to calculate offsetWidth/Height.  Overridden by inlines (RenderFlow)
+    // to return the remaining width on a given line (and the height of a single line).
+    virtual int offsetWidth() const { return width(); }
+    virtual int offsetHeight() const { return height(); }
+
+    // More IE extensions.  clientWidth and clientHeight represent the interior of an object
+    // excluding border and scrollbar.  clientLeft/Top are just the borderLeftWidth and borderTopWidth.
+    int clientLeft() const { return borderLeft(); }
+    int clientTop() const { return borderTop(); }
+    int clientWidth() const;
+    int clientHeight() const;
+    int clientLogicalBottom() const { return style()->isHorizontalWritingMode() ? clientTop() + clientHeight() : clientLeft() + clientWidth(); }
+    IntRect clientBoxRect() const { return IntRect(clientLeft(), clientTop(), clientWidth(), clientHeight()); }
+
+    // scrollWidth/scrollHeight will be the same as clientWidth/clientHeight unless the
+    // object has overflow:hidden/scroll/auto specified and also has overflow.
+    // scrollLeft/Top return the current scroll position.  These methods are virtual so that objects like
+    // textareas can scroll shadow content (but pretend that they are the objects that are
+    // scrolling).
+    virtual int scrollLeft() const;
+    virtual int scrollTop() const;
+    virtual int scrollWidth() const;
+    virtual int scrollHeight() const;
+    virtual void setScrollLeft(int);
+    virtual void setScrollTop(int);
+
+    virtual int marginTop() const { return m_marginTop; }
+    virtual int marginBottom() const { return m_marginBottom; }
+    virtual int marginLeft() const { return m_marginLeft; }
+    virtual int marginRight() const { return m_marginRight; }
+    void setMarginTop(int margin) { m_marginTop = margin; }
+    void setMarginBottom(int margin) { m_marginBottom = margin; }
+    void setMarginLeft(int margin) { m_marginLeft = margin; }
+    void setMarginRight(int margin) { m_marginRight = margin; }
+    virtual int marginBefore() const;
+    virtual int marginAfter() const;
+    virtual int marginStart() const;
+    virtual int marginEnd() const;
+    void setMarginStart(int);
+    void setMarginEnd(int);
+    void setMarginBefore(int);
+    void setMarginAfter(int);
+
+    // The following five functions are used to implement collapsing margins.
+    // All objects know their maximal positive and negative margins.  The
+    // formula for computing a collapsed margin is |maxPosMargin| - |maxNegmargin|.
+    // For a non-collapsing box, such as a leaf element, this formula will simply return
+    // the margin of the element.  Blocks override the maxMarginBefore and maxMarginAfter
+    // methods.
+    enum MarginSign { PositiveMargin, NegativeMargin };
+    virtual bool isSelfCollapsingBlock() const { return false; }
+    virtual int collapsedMarginBefore() const { return marginBefore(); }
+    virtual int collapsedMarginAfter() const { return marginAfter(); }
+
+    virtual void absoluteRects(Vector<IntRect>&, int tx, int ty);
+    virtual void absoluteQuads(Vector<FloatQuad>&);
+    
+    IntRect reflectionBox() const;
+    int reflectionOffset() const;
+    // Given a rect in the object's coordinate space, returns the corresponding rect in the reflection.
+    IntRect reflectedRect(const IntRect&) const;
+
+    virtual void layout();
+    virtual void paint(PaintInfo&, int tx, int ty);
+    virtual bool nodeAtPoint(const HitTestRequest&, HitTestResult&, int x, int y, int tx, int ty, HitTestAction);
+
+    virtual void destroy();
+
+    virtual int minPreferredLogicalWidth() const;
+    virtual int maxPreferredLogicalWidth() const;
+
+    int overrideSize() const;
+    int overrideWidth() const;
+    int overrideHeight() const;
+    virtual void setOverrideSize(int);
+
+    virtual IntSize offsetFromContainer(RenderObject*, const IntPoint&) const;
+    
+    int computeBorderBoxLogicalWidth(int width) const;
+    int computeBorderBoxLogicalHeight(int height) const;
+    int computeContentBoxLogicalWidth(int width) const;
+    int computeContentBoxLogicalHeight(int height) const;
+
+    virtual void borderFitAdjust(int& /*x*/, int& /*w*/) const { } // Shrink the box in which the border paints if border-fit is set.
+
+    // Resolve auto margins in the inline direction of the containing block so that objects can be pushed to the start, middle or end
+    // of the containing block.
+    void computeInlineDirectionMargins(RenderBlock* containingBlock, int containerWidth, int childWidth);
+
+    // Used to resolve margins in the containing block's block-flow direction.
+    void computeBlockDirectionMargins(RenderBlock* containingBlock);
+
+    void positionLineBox(InlineBox*);
+
+    virtual InlineBox* createInlineBox();
+    void dirtyLineBoxes(bool fullLayout);
+
+    // For inline replaced elements, this function returns the inline box that owns us.  Enables
+    // the replaced RenderObject to quickly determine what line it is contained on and to easily
+    // iterate over structures on the line.
+    InlineBox* inlineBoxWrapper() const { return m_inlineBoxWrapper; }
+    void setInlineBoxWrapper(InlineBox* boxWrapper) { m_inlineBoxWrapper = boxWrapper; }
+    void deleteLineBoxWrapper();
+
+    virtual IntRect clippedOverflowRectForRepaint(RenderBoxModelObject* repaintContainer);
+    virtual void computeRectForRepaint(RenderBoxModelObject* repaintContainer, IntRect&, bool fixed = false);
+
+    virtual void repaintDuringLayoutIfMoved(const IntRect&);
+
+    virtual int containingBlockLogicalWidthForContent() const;
+    int perpendicularContainingBlockLogicalHeight() const;
+    
+    virtual void computeLogicalWidth();
+    virtual void computeLogicalHeight();
+
+    bool stretchesToViewport() const
+    {
+        return document()->inQuirksMode() && style()->logicalHeight().isAuto() && !isFloatingOrPositioned() && (isRoot() || isBody());
+    }
+
+    virtual IntSize intrinsicSize() const { return IntSize(); }
+    int intrinsicLogicalWidth() const { return style()->isHorizontalWritingMode() ? intrinsicSize().width() : intrinsicSize().height(); }
+    int intrinsicLogicalHeight() const { return style()->isHorizontalWritingMode() ? intrinsicSize().height() : intrinsicSize().width(); }
+
+    // Whether or not the element shrinks to its intrinsic width (rather than filling the width
+    // of a containing block).  HTML4 buttons, <select>s, <input>s, legends, and floating/compact elements do this.
+    bool sizesToIntrinsicLogicalWidth(LogicalWidthType) const;
+    virtual bool stretchesToMinIntrinsicLogicalWidth() const { return false; }
+
+    int computeLogicalWidthUsing(LogicalWidthType, int availableLogicalWidth);
+    int computeLogicalHeightUsing(const Length& height);
+    int computeReplacedLogicalWidthUsing(Length width) const;
+    int computeReplacedLogicalHeightUsing(Length height) const;
+
+    virtual int computeReplacedLogicalWidth(bool includeMaxWidth = true) const;
+    virtual int computeReplacedLogicalHeight() const;
+
+    int computePercentageLogicalHeight(const Length& height);
+
+    // Block flows subclass availableWidth to handle multi column layout (shrinking the width available to children when laying out.)
+    virtual int availableLogicalWidth() const { return contentLogicalWidth(); }
+    int availableLogicalHeight() const;
+    int availableLogicalHeightUsing(const Length&) const;
+    
+    // There are a few cases where we need to refer specifically to the available physical width and available physical height.
+    // Relative positioning is one of those cases, since left/top offsets are physical.
+    int availableWidth() const { return style()->isHorizontalWritingMode() ? availableLogicalWidth() : availableLogicalHeight(); }
+    int availableHeight() const { return style()->isHorizontalWritingMode() ? availableLogicalHeight() : availableLogicalWidth(); }
+
+    virtual int verticalScrollbarWidth() const;
+    int horizontalScrollbarHeight() const;
+    int scrollbarLogicalHeight() const { return style()->isHorizontalWritingMode() ? horizontalScrollbarHeight() : verticalScrollbarWidth(); }
+    virtual bool scroll(ScrollDirection, ScrollGranularity, float multiplier = 1, Node** stopNode = 0);
+    virtual bool logicalScroll(ScrollLogicalDirection, ScrollGranularity, float multiplier = 1, Node** stopNode = 0);
+    bool canBeScrolledAndHasScrollableArea() const;
+    virtual bool canBeProgramaticallyScrolled(bool) const;
+    virtual void autoscroll();
+    virtual void stopAutoscroll() { }
+    virtual void panScroll(const IntPoint&);
+    bool hasAutoVerticalScrollbar() const { return hasOverflowClip() && (style()->overflowY() == OAUTO || style()->overflowY() == OOVERLAY); }
+    bool hasAutoHorizontalScrollbar() const { return hasOverflowClip() && (style()->overflowX() == OAUTO || style()->overflowX() == OOVERLAY); }
+    bool scrollsOverflow() const { return scrollsOverflowX() || scrollsOverflowY(); }
+    bool scrollsOverflowX() const { return hasOverflowClip() && (style()->overflowX() == OSCROLL || hasAutoHorizontalScrollbar()); }
+    bool scrollsOverflowY() const { return hasOverflowClip() && (style()->overflowY() == OSCROLL || hasAutoVerticalScrollbar()); }
+    
+    virtual IntRect localCaretRect(InlineBox*, int caretOffset, int* extraWidthToEndOfLine = 0);
+
+    virtual IntRect overflowClipRect(int tx, int ty);
+    IntRect clipRect(int tx, int ty);
+    virtual bool hasControlClip() const { return false; }
+    virtual IntRect controlClipRect(int /*tx*/, int /*ty*/) const { return IntRect(); }
+    bool pushContentsClip(PaintInfo&, int tx, int ty);
+    void popContentsClip(PaintInfo&, PaintPhase originalPhase, int tx, int ty);
+
+    virtual void paintObject(PaintInfo&, int /*tx*/, int /*ty*/) { ASSERT_NOT_REACHED(); }
+    virtual void paintBoxDecorations(PaintInfo&, int tx, int ty);
+    virtual void paintMask(PaintInfo&, int tx, int ty);
+    virtual void imageChanged(WrappedImagePtr, const IntRect* = 0);
+
+    // Called when a positioned object moves but doesn't necessarily change size.  A simplified layout is attempted
+    // that just updates the object's position. If the size does change, the object remains dirty.
+    void tryLayoutDoingPositionedMovementOnly()
+    {
+        int oldWidth = width();
+        computeLogicalWidth();
+        // If we shrink to fit our width may have changed, so we still need full layout.
+        if (oldWidth != width())
+            return;
+        computeLogicalHeight();
+        setNeedsLayout(false);
+    }
+
+    IntRect maskClipRect();
+
+    virtual VisiblePosition positionForPoint(const IntPoint&);
+
+    void removeFloatingOrPositionedChildFromBlockLists();
+    
+    RenderLayer* enclosingFloatPaintingLayer() const;
+    
+    virtual int firstLineBoxBaseline() const { return -1; }
+    virtual int lastLineBoxBaseline() const { return -1; }
+
+    bool shrinkToAvoidFloats() const;
+    virtual bool avoidsFloats() const;
+
+    virtual void markForPaginationRelayoutIfNeeded() { }
+
+    bool isWritingModeRoot() const { return !parent() || parent()->style()->writingMode() != style()->writingMode(); }
+    
+    virtual int lineHeight(bool firstLine, LineDirectionMode, LinePositionMode = PositionOnContainingLine) const;
+    virtual int baselinePosition(FontBaseline, bool firstLine, LineDirectionMode, LinePositionMode = PositionOnContainingLine) const;
+
+    enum FlippingAdjustment { ChildToParentFlippingAdjustment, ParentToChildFlippingAdjustment };
+    IntPoint flipForWritingMode(const RenderBox* child, const IntPoint&, FlippingAdjustment) const;
+    int flipForWritingMode(int position) const; // The offset is in the block direction (y for horizontal writing modes, x for vertical writing modes).
+    IntPoint flipForWritingMode(const IntPoint&) const;
+    IntSize flipForWritingMode(const IntSize&) const;
+    void flipForWritingMode(IntRect&) const;
+    IntSize locationOffsetIncludingFlipping() const;
+
+    IntRect logicalVisualOverflowRectForPropagation(RenderStyle*) const;
+    IntRect visualOverflowRectForPropagation(RenderStyle*) const;
+    IntRect logicalLayoutOverflowRectForPropagation(RenderStyle*) const;
+    IntRect layoutOverflowRectForPropagation(RenderStyle*) const;
+
+#ifdef ANDROID_LAYOUT
+    int getVisibleWidth() const { return m_visibleWidth; }
+#endif
+
+protected:
+    virtual void styleWillChange(StyleDifference, const RenderStyle* newStyle);
+    virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle);
+    virtual void updateBoxModelInfoFromStyle();
+
+    void paintFillLayer(const PaintInfo&, const Color&, const FillLayer*, int tx, int ty, int width, int height, CompositeOperator op, RenderObject* backgroundObject);
+    void paintFillLayers(const PaintInfo&, const Color&, const FillLayer*, int tx, int ty, int width, int height, CompositeOperator = CompositeSourceOver, RenderObject* backgroundObject = 0);
+
+    void paintBoxDecorationsWithSize(PaintInfo&, int tx, int ty, int width, int height);
+    void paintMaskImages(const PaintInfo&, int tx, int ty, int width, int height);
+
+#if PLATFORM(MAC)
+    void paintCustomHighlight(int tx, int ty, const AtomicString& type, bool behindText);
+#endif
+
+    void computePositionedLogicalWidth();
+    
+    virtual bool shouldComputeSizeAsReplaced() const { return isReplaced() && !isInlineBlockOrInlineTable(); }
+
+    virtual void mapLocalToContainer(RenderBoxModelObject* repaintContainer, bool fixed, bool useTransforms, TransformState&) const;
+    virtual void mapAbsoluteToLocalPoint(bool fixed, bool useTransforms, TransformState&) const;
+
+private:
+    bool includeVerticalScrollbarSize() const { return hasOverflowClip() && (style()->overflowY() == OSCROLL || style()->overflowY() == OAUTO); }
+    bool includeHorizontalScrollbarSize() const { return hasOverflowClip() && (style()->overflowX() == OSCROLL || style()->overflowX() == OAUTO); }
+
+    void paintRootBoxDecorations(PaintInfo&, int tx, int ty);
+    // Returns true if we did a full repaint
+    bool repaintLayerRectsForImage(WrappedImagePtr image, const FillLayer* layers, bool drawingBackground);
+   
+    int containingBlockWidthForPositioned(const RenderBoxModelObject* containingBlock) const;
+    int containingBlockHeightForPositioned(const RenderBoxModelObject* containingBlock) const;
+
+    void computePositionedLogicalHeight();
+    void computePositionedLogicalWidthUsing(Length width, const RenderBoxModelObject* cb, TextDirection containerDirection,
+                                      int containerWidth, int bordersPlusPadding,
+                                      Length left, Length right, Length marginLeft, Length marginRight,
+                                      int& widthValue, int& marginLeftValue, int& marginRightValue, int& xPos);
+    void computePositionedLogicalHeightUsing(Length height, const RenderBoxModelObject* cb,
+                                    int containerHeight, int bordersPlusPadding,
+                                    Length top, Length bottom, Length marginTop, Length marginBottom,
+                                    int& heightValue, int& marginTopValue, int& marginBottomValue, int& yPos);
+
+    void computePositionedLogicalHeightReplaced();
+    void computePositionedLogicalWidthReplaced();
+
+    // This function calculates the minimum and maximum preferred widths for an object.
+    // These values are used in shrink-to-fit layout systems.
+    // These include tables, positioned objects, floats and flexible boxes.
+    virtual void computePreferredLogicalWidths() { setPreferredLogicalWidthsDirty(false); }
+
+private:
+    // The width/height of the contents + borders + padding.  The x/y location is relative to our container (which is not always our parent).
+    IntRect m_frameRect;
+
+protected:
+
+#ifdef ANDROID_LAYOUT
+    void setVisibleWidth(int newWidth);
+    bool checkAndSetRelayoutChildren(bool* relayoutChildren);
+#endif
+
+    int m_marginLeft;
+    int m_marginRight;
+    int m_marginTop;
+    int m_marginBottom;
+
+    // The preferred logical width of the element if it were to break its lines at every possible opportunity.
+    int m_minPreferredLogicalWidth;
+    
+    // The preferred logical width of the element if it never breaks any lines at all.
+    int m_maxPreferredLogicalWidth;
+
+    // For inline replaced elements, the inline box that owns us.
+    InlineBox* m_inlineBoxWrapper;
+
+    // Our overflow information.
+    OwnPtr<RenderOverflow> m_overflow;
+
+private:
+    // Used to store state between styleWillChange and styleDidChange
+    static bool s_hadOverflowClip;
+
+#ifdef ANDROID_LAYOUT
+    int m_visibleWidth;
+    bool m_isVisibleWidthChangedBeforeLayout;
+#endif
+};
+
+inline RenderBox* toRenderBox(RenderObject* object)
+{ 
+    ASSERT(!object || object->isBox());
+    return static_cast<RenderBox*>(object);
+}
+
+inline const RenderBox* toRenderBox(const RenderObject* object)
+{ 
+    ASSERT(!object || object->isBox());
+    return static_cast<const RenderBox*>(object);
+}
+
+// This will catch anyone doing an unnecessary cast.
+void toRenderBox(const RenderBox*);
+
+inline RenderBox* RenderBox::previousSiblingBox() const
+{
+    return toRenderBox(previousSibling());
+}
+
+inline RenderBox* RenderBox::nextSiblingBox() const
+{ 
+    return toRenderBox(nextSibling());
+}
+
+inline RenderBox* RenderBox::parentBox() const
+{
+    return toRenderBox(parent());
+}
+
+inline RenderBox* RenderBox::firstChildBox() const
+{
+    return toRenderBox(firstChild());
+}
+
+inline RenderBox* RenderBox::lastChildBox() const
+{
+    return toRenderBox(lastChild());
+}
+
+} // namespace WebCore
+
+#endif // RenderBox_h