Imported WebKit commit 2ea9d364d0f6efa8fa64acf19f451504c59be0e4 (http://svn.webkit.org/repository/webkit/trunk@104285)

1 files changed, 1092 insertions, 0 deletions

diff --git a/Source/WebCore/rendering/RenderBlock.h b/Source/WebCore/rendering/RenderBlock.h
new file mode 100644
index 000000000..20aafb990
--- /dev/null
+++ b/Source/WebCore/rendering/RenderBlock.h
@@ -0,0 +1,1092 @@
+/*
+ * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
+ *           (C) 1999 Antti Koivisto (koivisto@kde.org)
+ *           (C) 2007 David Smith (catfish.man@gmail.com)
+ * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 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 RenderBlock_h
+#define RenderBlock_h
+
+#include "GapRects.h"
+#include "PODIntervalTree.h"
+#include "RenderBox.h"
+#include "RenderLineBoxList.h"
+#include "RootInlineBox.h"
+#include "TextRun.h"
+#include <wtf/OwnPtr.h>
+#include <wtf/ListHashSet.h>
+
+namespace WebCore {
+
+class BidiContext;
+class ColumnInfo;
+class InlineIterator;
+class LayoutStateMaintainer;
+class LazyLineBreakIterator;
+class LineLayoutState;
+class LineWidth;
+class RenderInline;
+class RenderText;
+
+struct BidiRun;
+struct PaintInfo;
+class LineInfo;
+class RenderRubyRun;
+
+template <class Iterator, class Run> class BidiResolver;
+template <class Run> class BidiRunList;
+template <class Iterator> struct MidpointState;
+typedef BidiResolver<InlineIterator, BidiRun> InlineBidiResolver;
+typedef MidpointState<InlineIterator> LineMidpointState;
+
+enum CaretType { CursorCaret, DragCaret };
+
+enum TextRunFlag {
+    DefaultTextRunFlags = 0,
+    RespectDirection = 1 << 0,
+    RespectDirectionOverride = 1 << 1
+};
+
+typedef unsigned TextRunFlags;
+
+class RenderBlock : public RenderBox {
+public:
+    friend class LineLayoutState;
+#ifndef NDEBUG
+    // Used by the PODIntervalTree for debugging the FloatingObject.
+    template <class> friend struct ValueToString;
+#endif
+
+    RenderBlock(Node*);
+    virtual ~RenderBlock();
+
+    const RenderObjectChildList* children() const { return &m_children; }
+    RenderObjectChildList* children() { return &m_children; }
+
+    bool beingDestroyed() const { return m_beingDestroyed; }
+
+    // These two functions are overridden for inline-block.
+    virtual LayoutUnit lineHeight(bool firstLine, LineDirectionMode, LinePositionMode = PositionOnContainingLine) const;
+    virtual LayoutUnit baselinePosition(FontBaseline, bool firstLine, LineDirectionMode, LinePositionMode = PositionOnContainingLine) const;
+
+    RenderLineBoxList* lineBoxes() { return &m_lineBoxes; }
+    const RenderLineBoxList* lineBoxes() const { return &m_lineBoxes; }
+
+    InlineFlowBox* firstLineBox() const { return m_lineBoxes.firstLineBox(); }
+    InlineFlowBox* lastLineBox() const { return m_lineBoxes.lastLineBox(); }
+
+    void deleteLineBoxTree();
+
+    virtual void addChild(RenderObject* newChild, RenderObject* beforeChild = 0);
+    virtual void removeChild(RenderObject*);
+
+    enum BlockLayoutPass { NormalLayoutPass, PositionedFloatLayoutPass };
+    virtual void layoutBlock(bool relayoutChildren, LayoutUnit pageLogicalHeight = 0, BlockLayoutPass = NormalLayoutPass);
+
+    void insertPositionedObject(RenderBox*);
+    void removePositionedObject(RenderBox*);
+    void removePositionedObjects(RenderBlock*);
+
+    typedef ListHashSet<RenderBox*, 4> PositionedObjectsListHashSet;
+    PositionedObjectsListHashSet* positionedObjects() const { return m_positionedObjects.get(); }
+
+    void addPercentHeightDescendant(RenderBox*);
+    static void removePercentHeightDescendant(RenderBox*);
+    HashSet<RenderBox*>* percentHeightDescendants() const;
+#if !ASSERT_DISABLED
+    static bool hasPercentHeightDescendant(RenderBox*);
+#endif
+
+    RootInlineBox* createAndAppendRootInlineBox();
+
+    bool generatesLineBoxesForInlineChild(RenderObject*);
+
+    void markAllDescendantsWithFloatsForLayout(RenderBox* floatToRemove = 0, bool inLayout = true);
+    void markSiblingsWithFloatsForLayout();
+    void markPositionedObjectsForLayout();
+    virtual void markForPaginationRelayoutIfNeeded();
+    
+    bool containsFloats() { return m_floatingObjects && !m_floatingObjects->set().isEmpty(); }
+    bool containsFloat(RenderBox*);
+
+    // Versions that can compute line offsets with the region and page offset passed in. Used for speed to avoid having to
+    // compute the region all over again when you already know it.
+    LayoutUnit availableLogicalWidthForLine(LayoutUnit position, bool firstLine, RenderRegion* region, LayoutUnit offsetFromLogicalTopOfFirstPage) const
+    {
+        return max<LayoutUnit>(0, logicalRightOffsetForLine(position, firstLine, region, offsetFromLogicalTopOfFirstPage)
+            - logicalLeftOffsetForLine(position, firstLine, region, offsetFromLogicalTopOfFirstPage));
+    }
+    LayoutUnit logicalRightOffsetForLine(LayoutUnit position, bool firstLine, RenderRegion* region, LayoutUnit offsetFromLogicalTopOfFirstPage) const 
+    {
+        return logicalRightOffsetForLine(position, logicalRightOffsetForContent(region, offsetFromLogicalTopOfFirstPage), firstLine);
+    }
+    LayoutUnit logicalLeftOffsetForLine(LayoutUnit position, bool firstLine, RenderRegion* region, LayoutUnit offsetFromLogicalTopOfFirstPage) const 
+    {
+        return logicalLeftOffsetForLine(position, logicalLeftOffsetForContent(region, offsetFromLogicalTopOfFirstPage), firstLine);
+    }
+    LayoutUnit startOffsetForLine(LayoutUnit position, bool firstLine, RenderRegion* region, LayoutUnit offsetFromLogicalTopOfFirstPage) const
+    {
+        return style()->isLeftToRightDirection() ? logicalLeftOffsetForLine(position, firstLine, region, offsetFromLogicalTopOfFirstPage)
+            : logicalWidth() - logicalRightOffsetForLine(position, firstLine, region, offsetFromLogicalTopOfFirstPage);
+    }
+
+    LayoutUnit availableLogicalWidthForLine(LayoutUnit position, bool firstLine) const
+    {
+        return availableLogicalWidthForLine(position, firstLine, regionAtBlockOffset(position), offsetFromLogicalTopOfFirstPage());
+    }
+    LayoutUnit logicalRightOffsetForLine(LayoutUnit position, bool firstLine) const 
+    {
+        return logicalRightOffsetForLine(position, logicalRightOffsetForContent(position), firstLine, 0);
+    }
+    LayoutUnit logicalLeftOffsetForLine(LayoutUnit position, bool firstLine) const 
+    {
+        return logicalLeftOffsetForLine(position, logicalLeftOffsetForContent(position), firstLine, 0);
+    }
+    LayoutUnit startOffsetForLine(LayoutUnit position, bool firstLine) const
+    {
+        return style()->isLeftToRightDirection() ? logicalLeftOffsetForLine(position, firstLine)
+            : logicalWidth() - logicalRightOffsetForLine(position, firstLine);
+    }
+    
+    LayoutUnit startAlignedOffsetForLine(RenderBox* child, LayoutUnit position, bool firstLine);
+    LayoutUnit textIndentOffset() const;
+
+    virtual VisiblePosition positionForPoint(const LayoutPoint&);
+    
+    // Block flows subclass availableWidth to handle multi column layout (shrinking the width available to children when laying out.)
+    virtual LayoutUnit availableLogicalWidth() const;
+
+    LayoutPoint flipForWritingModeIncludingColumns(const LayoutPoint&) const;
+    void adjustStartEdgeForWritingModeIncludingColumns(LayoutRect&) const;
+
+    RootInlineBox* firstRootBox() const { return static_cast<RootInlineBox*>(firstLineBox()); }
+    RootInlineBox* lastRootBox() const { return static_cast<RootInlineBox*>(lastLineBox()); }
+
+    bool containsNonZeroBidiLevel() const;
+
+    GapRects selectionGapRectsForRepaint(RenderBoxModelObject* repaintContainer);
+    LayoutRect logicalLeftSelectionGap(RenderBlock* rootBlock, const LayoutPoint& rootBlockPhysicalPosition, const LayoutSize& offsetFromRootBlock,
+                                       RenderObject* selObj, LayoutUnit logicalLeft, LayoutUnit logicalTop, LayoutUnit logicalHeight, const PaintInfo*);
+    LayoutRect logicalRightSelectionGap(RenderBlock* rootBlock, const LayoutPoint& rootBlockPhysicalPosition, const LayoutSize& offsetFromRootBlock,
+                                        RenderObject* selObj, LayoutUnit logicalRight, LayoutUnit logicalTop, LayoutUnit logicalHeight, const PaintInfo*);
+    void getSelectionGapInfo(SelectionState, bool& leftGap, bool& rightGap);
+    LayoutRect logicalRectToPhysicalRect(const LayoutPoint& physicalPosition, const LayoutRect& logicalRect);
+        
+    // Helper methods for computing line counts and heights for line counts.
+    RootInlineBox* lineAtIndex(int);
+    int lineCount();
+    int heightForLineCount(int);
+    void clearTruncation();
+
+    void adjustRectForColumns(LayoutRect&) const;
+    virtual void adjustForColumns(LayoutSize&, const LayoutPoint&) const;
+    void adjustForColumnRect(LayoutSize& offset, const LayoutPoint& pointInContainer) const;
+
+    void addContinuationWithOutline(RenderInline*);
+    bool paintsContinuationOutline(RenderInline*);
+
+    virtual RenderBoxModelObject* virtualContinuation() const { return continuation(); }
+    bool isAnonymousBlockContinuation() const { return continuation() && isAnonymousBlock(); }
+    RenderInline* inlineElementContinuation() const;
+    RenderBlock* blockElementContinuation() const;
+
+    using RenderBoxModelObject::continuation;
+    using RenderBoxModelObject::setContinuation;
+
+    // This function is a convenience helper for creating an anonymous block that inherits its
+    // style from this RenderBlock.
+    RenderBlock* createAnonymousBlock(bool isFlexibleBox = false) const;
+    RenderBlock* createAnonymousColumnsBlock() const;
+    RenderBlock* createAnonymousColumnSpanBlock() const;
+    RenderBlock* createAnonymousBlockWithSameTypeAs(RenderBlock* otherAnonymousBlock) const;
+    
+    static void appendRunsForObject(BidiRunList<BidiRun>&, int start, int end, RenderObject*, InlineBidiResolver&);
+
+    static TextRun constructTextRun(RenderObject* context, const Font&, const String&, RenderStyle*,
+                                    TextRun::ExpansionBehavior = TextRun::AllowTrailingExpansion | TextRun::ForbidLeadingExpansion, TextRunFlags = DefaultTextRunFlags);
+
+    static TextRun constructTextRun(RenderObject* context, const Font&, const UChar*, int length, RenderStyle*,
+                                    TextRun::ExpansionBehavior = TextRun::AllowTrailingExpansion | TextRun::ForbidLeadingExpansion, TextRunFlags = DefaultTextRunFlags);
+
+    ColumnInfo* columnInfo() const;
+    int columnGap() const;
+    
+    // These two functions take the ColumnInfo* to avoid repeated lookups of the info in the global HashMap.
+    unsigned columnCount(ColumnInfo*) const;
+    LayoutRect columnRectAt(ColumnInfo*, unsigned) const;
+
+    LayoutUnit paginationStrut() const { return m_rareData ? m_rareData->m_paginationStrut : 0; }
+    void setPaginationStrut(LayoutUnit);
+    
+    // The page logical offset is the object's offset from the top of the page in the page progression
+    // direction (so an x-offset in vertical text and a y-offset for horizontal text).
+    int pageLogicalOffset() const { return m_rareData ? m_rareData->m_pageLogicalOffset : 0; }
+    void setPageLogicalOffset(int);
+
+    // Accessors for logical width/height and margins in the containing block's block-flow direction.
+    enum ApplyLayoutDeltaMode { ApplyLayoutDelta, DoNotApplyLayoutDelta };
+    LayoutUnit logicalWidthForChild(const RenderBox* child) { return isHorizontalWritingMode() ? child->width() : child->height(); }
+    LayoutUnit logicalHeightForChild(const RenderBox* child) { return isHorizontalWritingMode() ? child->height() : child->width(); }
+    LayoutUnit logicalTopForChild(const RenderBox* child) { return isHorizontalWritingMode() ? child->y() : child->x(); }
+    LayoutUnit logicalLeftForChild(const RenderBox* child) { return isHorizontalWritingMode() ? child->x() : child->y(); }
+    void setLogicalLeftForChild(RenderBox* child, LayoutUnit logicalLeft, ApplyLayoutDeltaMode = DoNotApplyLayoutDelta);
+    void setLogicalTopForChild(RenderBox* child, LayoutUnit logicalTop, ApplyLayoutDeltaMode = DoNotApplyLayoutDelta);
+    LayoutUnit marginBeforeForChild(const RenderBoxModelObject* child) const;
+    LayoutUnit marginAfterForChild(const RenderBoxModelObject* child) const;
+    LayoutUnit marginStartForChild(const RenderBoxModelObject* child) const;
+    LayoutUnit marginEndForChild(const RenderBoxModelObject* child) const;
+    LayoutUnit marginLogicalLeftForChild(const RenderBoxModelObject* child) const;
+    LayoutUnit marginLogicalRightForChild(const RenderBoxModelObject* child) const;
+    void setMarginStartForChild(RenderBox* child, LayoutUnit);
+    void setMarginEndForChild(RenderBox* child, LayoutUnit);
+    void setMarginBeforeForChild(RenderBox* child, LayoutUnit);
+    void setMarginAfterForChild(RenderBox* child, LayoutUnit);
+    LayoutUnit collapsedMarginBeforeForChild(const RenderBox* child) const;
+    LayoutUnit collapsedMarginAfterForChild(const RenderBox* child) const;
+
+    void updateLogicalWidthForAlignment(const ETextAlign&, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float& availableLogicalWidth, int expansionOpportunityCount);
+
+    virtual void updateFirstLetter();
+
+    class MarginValues {
+    public:
+        MarginValues(LayoutUnit beforePos, LayoutUnit beforeNeg, LayoutUnit afterPos, LayoutUnit afterNeg)
+            : m_positiveMarginBefore(beforePos)
+            , m_negativeMarginBefore(beforeNeg)
+            , m_positiveMarginAfter(afterPos)
+            , m_negativeMarginAfter(afterNeg)
+        { }
+        
+        LayoutUnit positiveMarginBefore() const { return m_positiveMarginBefore; }
+        LayoutUnit negativeMarginBefore() const { return m_negativeMarginBefore; }
+        LayoutUnit positiveMarginAfter() const { return m_positiveMarginAfter; }
+        LayoutUnit negativeMarginAfter() const { return m_negativeMarginAfter; }
+        
+        void setPositiveMarginBefore(LayoutUnit pos) { m_positiveMarginBefore = pos; }
+        void setNegativeMarginBefore(LayoutUnit neg) { m_negativeMarginBefore = neg; }
+        void setPositiveMarginAfter(LayoutUnit pos) { m_positiveMarginAfter = pos; }
+        void setNegativeMarginAfter(LayoutUnit neg) { m_negativeMarginAfter = neg; }
+    
+    private:
+        LayoutUnit m_positiveMarginBefore;
+        LayoutUnit m_negativeMarginBefore;
+        LayoutUnit m_positiveMarginAfter;
+        LayoutUnit m_negativeMarginAfter;
+    };
+    MarginValues marginValuesForChild(RenderBox* child);
+
+    virtual void scrollbarsChanged(bool /*horizontalScrollbarChanged*/, bool /*verticalScrollbarChanged*/) { };
+
+    LayoutUnit logicalLeftOffsetForContent(RenderRegion*, LayoutUnit offsetFromLogicalTopOfFirstPage) const;
+    LayoutUnit logicalRightOffsetForContent(RenderRegion*, LayoutUnit offsetFromLogicalTopOfFirstPage) const;
+    LayoutUnit availableLogicalWidthForContent(RenderRegion* region, LayoutUnit offsetFromLogicalTopOfFirstPage) const
+    { 
+        return max<LayoutUnit>(0, logicalRightOffsetForContent(region, offsetFromLogicalTopOfFirstPage) -
+            logicalLeftOffsetForContent(region, offsetFromLogicalTopOfFirstPage)); }
+    LayoutUnit startOffsetForContent(RenderRegion* region, LayoutUnit offsetFromLogicalTopOfFirstPage) const
+    {
+        return style()->isLeftToRightDirection() ? logicalLeftOffsetForContent(region, offsetFromLogicalTopOfFirstPage)
+            : logicalWidth() - logicalRightOffsetForContent(region, offsetFromLogicalTopOfFirstPage);
+    }
+    LayoutUnit logicalLeftOffsetForContent(LayoutUnit blockOffset) const
+    {
+        return logicalLeftOffsetForContent(regionAtBlockOffset(blockOffset), offsetFromLogicalTopOfFirstPage());
+    }
+    LayoutUnit logicalRightOffsetForContent(LayoutUnit blockOffset) const
+    {
+        return logicalRightOffsetForContent(regionAtBlockOffset(blockOffset), offsetFromLogicalTopOfFirstPage());
+    }
+    LayoutUnit availableLogicalWidthForContent(LayoutUnit blockOffset) const
+    {
+        return availableLogicalWidthForContent(regionAtBlockOffset(blockOffset), offsetFromLogicalTopOfFirstPage());
+    }
+    LayoutUnit startOffsetForContent(LayoutUnit blockOffset) const
+    {
+        return startOffsetForContent(regionAtBlockOffset(blockOffset), offsetFromLogicalTopOfFirstPage());
+    }
+    LayoutUnit logicalLeftOffsetForContent() const { return isHorizontalWritingMode() ? borderLeft() + paddingLeft() : borderTop() + paddingTop(); }
+    LayoutUnit logicalRightOffsetForContent() const { return logicalLeftOffsetForContent() + availableLogicalWidth(); }
+    LayoutUnit startOffsetForContent() const { return style()->isLeftToRightDirection() ? logicalLeftOffsetForContent() : logicalWidth() - logicalRightOffsetForContent(); }
+    
+    void setStaticInlinePositionForChild(RenderBox*, LayoutUnit blockOffset, LayoutUnit inlinePosition);
+
+    LayoutUnit computeStartPositionDeltaForChildAvoidingFloats(const RenderBox* child, LayoutUnit childMarginStart,
+        LayoutUnit childLogicalWidth, RenderRegion* = 0, LayoutUnit offsetFromLogicalTopOfFirstPage = 0);
+
+#ifndef NDEBUG
+    void showLineTreeAndMark(const InlineBox* = 0, const char* = 0, const InlineBox* = 0, const char* = 0, const RenderObject* = 0) const;
+#endif
+
+protected:
+    virtual void willBeDestroyed();
+
+    // These functions are only used internally to manipulate the render tree structure via remove/insert/appendChildNode.
+    // Since they are typically called only to move objects around within anonymous blocks (which only have layers in
+    // the case of column spans), the default for fullRemoveInsert is false rather than true.
+    void moveChildTo(RenderBlock* to, RenderObject* child, bool fullRemoveInsert = false)
+    {
+        return moveChildTo(to, child, 0, fullRemoveInsert);
+    }
+    void moveChildTo(RenderBlock* to, RenderObject* child, RenderObject* beforeChild, bool fullRemoveInsert = false);
+    void moveAllChildrenTo(RenderBlock* to, bool fullRemoveInsert = false)
+    {
+        return moveAllChildrenTo(to, 0, fullRemoveInsert);
+    }
+    void moveAllChildrenTo(RenderBlock* to, RenderObject* beforeChild, bool fullRemoveInsert = false)
+    {
+        return moveChildrenTo(to, firstChild(), 0, beforeChild, fullRemoveInsert);
+    }
+    // Move all of the kids from |startChild| up to but excluding |endChild|.  0 can be passed as the endChild to denote
+    // that all the kids from |startChild| onwards should be added.
+    void moveChildrenTo(RenderBlock* to, RenderObject* startChild, RenderObject* endChild, bool fullRemoveInsert = false)
+    {
+        return moveChildrenTo(to, startChild, endChild, 0, fullRemoveInsert);
+    }
+    void moveChildrenTo(RenderBlock* to, RenderObject* startChild, RenderObject* endChild, RenderObject* beforeChild, bool fullRemoveInsert = false);
+    
+    LayoutUnit maxPositiveMarginBefore() const { return m_rareData ? m_rareData->m_margins.positiveMarginBefore() : RenderBlockRareData::positiveMarginBeforeDefault(this); }
+    LayoutUnit maxNegativeMarginBefore() const { return m_rareData ? m_rareData->m_margins.negativeMarginBefore() : RenderBlockRareData::negativeMarginBeforeDefault(this); }
+    LayoutUnit maxPositiveMarginAfter() const { return m_rareData ? m_rareData->m_margins.positiveMarginAfter() : RenderBlockRareData::positiveMarginAfterDefault(this); }
+    LayoutUnit maxNegativeMarginAfter() const { return m_rareData ? m_rareData->m_margins.negativeMarginAfter() : RenderBlockRareData::negativeMarginAfterDefault(this); }
+    
+    void setMaxMarginBeforeValues(LayoutUnit pos, LayoutUnit neg);
+    void setMaxMarginAfterValues(LayoutUnit pos, LayoutUnit neg);
+
+    void initMaxMarginValues()
+    {
+        if (m_rareData) {
+            m_rareData->m_margins = MarginValues(RenderBlockRareData::positiveMarginBeforeDefault(this) , RenderBlockRareData::negativeMarginBeforeDefault(this),
+                                                 RenderBlockRareData::positiveMarginAfterDefault(this), RenderBlockRareData::negativeMarginAfterDefault(this));
+            m_rareData->m_paginationStrut = 0;
+        }
+    }
+
+    virtual void layout();
+
+    bool layoutPositionedObjects(bool relayoutChildren);
+
+    virtual void paint(PaintInfo&, const LayoutPoint&);
+    virtual void paintObject(PaintInfo&, const LayoutPoint&);
+   
+    LayoutUnit logicalRightOffsetForLine(LayoutUnit position, LayoutUnit fixedOffset, bool applyTextIndent, LayoutUnit* logicalHeightRemaining = 0) const;
+    LayoutUnit logicalLeftOffsetForLine(LayoutUnit position, LayoutUnit fixedOffset, bool applyTextIndent, LayoutUnit* logicalHeightRemaining = 0) const;
+
+    virtual ETextAlign textAlignmentForLine(bool endsWithSoftBreak) const;
+    virtual void adjustInlineDirectionLineBounds(int /* expansionOpportunityCount */, float& /* logicalLeft */, float& /* logicalWidth */) const { }
+
+    virtual bool nodeAtPoint(const HitTestRequest&, HitTestResult&, const LayoutPoint& pointInContainer, const LayoutPoint& accumulatedOffset, HitTestAction);
+
+    virtual void computePreferredLogicalWidths();
+
+    virtual LayoutUnit firstLineBoxBaseline() const;
+    virtual LayoutUnit lastLineBoxBaseline() const;
+
+    virtual void updateHitTestResult(HitTestResult&, const LayoutPoint&);
+
+    // Delay update scrollbar until finishDelayRepaint() will be
+    // called. This function is used when a flexbox is laying out its
+    // descendant. If multiple calls are made to startDelayRepaint(),
+    // finishDelayRepaint() will do nothing until finishDelayRepaint()
+    // is called the same number of times.
+    static void startDelayUpdateScrollInfo();
+    static void finishDelayUpdateScrollInfo();
+
+    virtual void styleWillChange(StyleDifference, const RenderStyle* newStyle);
+    virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle);
+
+    virtual bool hasLineIfEmpty() const;
+    
+    bool simplifiedLayout();
+    void simplifiedNormalFlowLayout();
+
+    void setDesiredColumnCountAndWidth(int, LayoutUnit);
+
+    void computeOverflow(LayoutUnit oldClientAfterEdge, bool recomputeFloats = false);
+    virtual void addOverflowFromChildren();
+    void addOverflowFromFloats();
+    void addOverflowFromPositionedObjects();
+    void addOverflowFromBlockChildren();
+    void addOverflowFromInlineChildren();
+    void addVisualOverflowFromTheme();
+
+    virtual void addFocusRingRects(Vector<LayoutRect>&, const LayoutPoint&);
+
+#if ENABLE(SVG)
+    // Only used by RenderSVGText, which explicitely overrides RenderBlock::layoutBlock(), do NOT use for anything else.
+    void forceLayoutInlineChildren()
+    {
+        LayoutUnit repaintLogicalTop = 0;
+        LayoutUnit repaintLogicalBottom = 0;
+        layoutInlineChildren(true, repaintLogicalTop, repaintLogicalBottom);
+    }
+#endif
+
+private:
+    virtual RenderObjectChildList* virtualChildren() { return children(); }
+    virtual const RenderObjectChildList* virtualChildren() const { return children(); }
+
+    virtual const char* renderName() const;
+
+    virtual bool isRenderBlock() const { return true; }
+    virtual bool isBlockFlow() const { return (!isInline() || isReplaced()) && !isTable(); }
+    virtual bool isInlineBlockOrInlineTable() const { return isInline() && isReplaced(); }
+
+    void makeChildrenNonInline(RenderObject* insertionPoint = 0);
+    virtual void removeLeftoverAnonymousBlock(RenderBlock* child);
+
+    virtual void dirtyLinesFromChangedChild(RenderObject* child) { m_lineBoxes.dirtyLinesFromChangedChild(this, child); }
+
+    void addChildToContinuation(RenderObject* newChild, RenderObject* beforeChild);
+    void addChildIgnoringContinuation(RenderObject* newChild, RenderObject* beforeChild);
+    void addChildToAnonymousColumnBlocks(RenderObject* newChild, RenderObject* beforeChild);
+    virtual void addChildIgnoringAnonymousColumnBlocks(RenderObject* newChild, RenderObject* beforeChild = 0);
+    
+    virtual bool isSelfCollapsingBlock() const;
+
+    virtual LayoutUnit collapsedMarginBefore() const { return maxPositiveMarginBefore() - maxNegativeMarginBefore(); }
+    virtual LayoutUnit collapsedMarginAfter() const { return maxPositiveMarginAfter() - maxNegativeMarginAfter(); }
+
+    virtual void repaintOverhangingFloats(bool paintAllDescendants);
+
+    void layoutBlockChildren(bool relayoutChildren, LayoutUnit& maxFloatLogicalBottom);
+    void layoutInlineChildren(bool relayoutChildren, LayoutUnit& repaintLogicalTop, LayoutUnit& repaintLogicalBottom);
+    BidiRun* handleTrailingSpaces(BidiRunList<BidiRun>&, BidiContext*);
+
+    virtual void borderFitAdjust(LayoutRect&) const; // Shrink the box in which the border paints if border-fit is set.
+
+    virtual void updateBeforeAfterContent(PseudoId);
+
+    virtual RootInlineBox* createRootInlineBox(); // Subclassed by SVG and Ruby.
+
+    // Called to lay out the legend for a fieldset or the ruby text of a ruby run.
+    virtual RenderObject* layoutSpecialExcludedChild(bool /*relayoutChildren*/) { return 0; }
+
+    struct FloatWithRect {
+        FloatWithRect(RenderBox* f)
+            : object(f)
+            , rect(LayoutRect(f->x() - f->marginLeft(), f->y() - f->marginTop(), f->width() + f->marginLeft() + f->marginRight(), f->height() + f->marginTop() + f->marginBottom()))
+            , everHadLayout(f->everHadLayout())
+        {
+        }
+
+        RenderBox* object;
+        LayoutRect rect;
+        bool everHadLayout;
+    };
+
+    struct FloatingObject {
+        WTF_MAKE_NONCOPYABLE(FloatingObject); WTF_MAKE_FAST_ALLOCATED;
+    public:
+        // FloatLeftRight is a mask to query for both left and right but not positioned.
+        // FloatAll is a mask to query for all types of floats.
+        enum Type { FloatLeft = 1, FloatRight = 2, FloatLeftRight = 3, FloatPositioned = 4, FloatAll = 7 };
+
+        FloatingObject(EFloat type)
+            : m_renderer(0)
+            , m_originatingLine(0)
+            , m_paginationStrut(0)
+            , m_shouldPaint(false)
+            , m_isDescendant(false)
+            , m_isPlaced(false)
+#ifndef NDEBUG
+            , m_isInPlacedTree(false)
+#endif
+        {
+            ASSERT(type != NoFloat);
+            if (type == LeftFloat)
+                m_type = FloatLeft;
+            else if (type == RightFloat)
+                m_type = FloatRight;
+            else if (type == PositionedFloat)
+                m_type = FloatPositioned;
+        }
+
+        FloatingObject(Type type, const LayoutRect& frameRect)
+            : m_renderer(0)
+            , m_originatingLine(0)
+            , m_frameRect(frameRect)
+            , m_paginationStrut(0)
+            , m_type(type)
+            , m_shouldPaint(type != FloatPositioned)
+            , m_isDescendant(false)
+            , m_isPlaced(true)
+#ifndef NDEBUG
+            , m_isInPlacedTree(false)
+#endif
+        {
+        }
+
+        Type type() const { return static_cast<Type>(m_type); }
+        RenderBox* renderer() const { return m_renderer; }
+        
+        bool isPlaced() const { return m_isPlaced; }
+        void setIsPlaced(bool placed = true) { m_isPlaced = placed; }
+
+        LayoutUnit x() const { ASSERT(isPlaced()); return m_frameRect.x(); }
+        LayoutUnit maxX() const { ASSERT(isPlaced()); return m_frameRect.maxX(); }
+        LayoutUnit y() const { ASSERT(isPlaced()); return m_frameRect.y(); }
+        LayoutUnit maxY() const { ASSERT(isPlaced()); return m_frameRect.maxY(); }
+        LayoutUnit width() const { return m_frameRect.width(); }
+        LayoutUnit height() const { return m_frameRect.height(); }
+
+        void setX(LayoutUnit x) { ASSERT(!isInPlacedTree()); m_frameRect.setX(x); }
+        void setY(LayoutUnit y) { ASSERT(!isInPlacedTree()); m_frameRect.setY(y); }
+        void setWidth(LayoutUnit width) { ASSERT(!isInPlacedTree()); m_frameRect.setWidth(width); }
+        void setHeight(LayoutUnit height) { ASSERT(!isInPlacedTree()); m_frameRect.setHeight(height); }
+
+        const LayoutRect& frameRect() const { ASSERT(isPlaced()); return m_frameRect; }
+        void setFrameRect(const LayoutRect& frameRect) { ASSERT(!isInPlacedTree()); m_frameRect = frameRect; }
+
+#ifndef NDEBUG
+        bool isInPlacedTree() const { return m_isInPlacedTree; }
+        void setIsInPlacedTree(bool value) { m_isInPlacedTree = value; }
+#endif
+
+        RenderBox* m_renderer;
+        RootInlineBox* m_originatingLine;
+        LayoutRect m_frameRect;
+        int m_paginationStrut;
+        unsigned m_type : 3; // Type (left/right aligned or positioned)
+        bool m_shouldPaint : 1;
+        bool m_isDescendant : 1;
+        bool m_isPlaced : 1;
+#ifndef NDEBUG
+        bool m_isInPlacedTree : 1;
+#endif
+    };
+
+    LayoutPoint flipFloatForWritingModeForChild(const FloatingObject*, const LayoutPoint&) const;
+
+    LayoutUnit logicalTopForFloat(const FloatingObject* child) const { return isHorizontalWritingMode() ? child->y() : child->x(); }
+    LayoutUnit logicalBottomForFloat(const FloatingObject* child) const { return isHorizontalWritingMode() ? child->maxY() : child->maxX(); }
+    LayoutUnit logicalLeftForFloat(const FloatingObject* child) const { return isHorizontalWritingMode() ? child->x() : child->y(); }
+    LayoutUnit logicalRightForFloat(const FloatingObject* child) const { return isHorizontalWritingMode() ? child->maxX() : child->maxY(); }
+    LayoutUnit logicalWidthForFloat(const FloatingObject* child) const { return isHorizontalWritingMode() ? child->width() : child->height(); }
+
+    void setLogicalTopForFloat(FloatingObject* child, LayoutUnit logicalTop)
+    {
+        if (isHorizontalWritingMode())
+            child->setY(logicalTop);
+        else
+            child->setX(logicalTop);
+    }
+    void setLogicalLeftForFloat(FloatingObject* child, LayoutUnit logicalLeft)
+    {
+        if (isHorizontalWritingMode())
+            child->setX(logicalLeft);
+        else
+            child->setY(logicalLeft);
+    }
+    void setLogicalHeightForFloat(FloatingObject* child, LayoutUnit logicalHeight)
+    {
+        if (isHorizontalWritingMode())
+            child->setHeight(logicalHeight);
+        else
+            child->setWidth(logicalHeight);
+    }
+    void setLogicalWidthForFloat(FloatingObject* child, LayoutUnit logicalWidth)
+    {
+        if (isHorizontalWritingMode())
+            child->setWidth(logicalWidth);
+        else
+            child->setHeight(logicalWidth);
+    }
+
+    LayoutUnit xPositionForFloatIncludingMargin(const FloatingObject* child) const
+    {
+        if (isHorizontalWritingMode())
+            return child->x() + child->renderer()->marginLeft();
+        else
+            return child->x() + marginBeforeForChild(child->renderer());
+    }
+        
+    LayoutUnit yPositionForFloatIncludingMargin(const FloatingObject* child) const
+    {
+        if (isHorizontalWritingMode())
+            return child->y() + marginBeforeForChild(child->renderer());
+        else
+            return child->y() + child->renderer()->marginTop();
+    }
+
+    LayoutPoint computeLogicalLocationForFloat(const FloatingObject*, LayoutUnit logicalTopOffset) const;
+
+    // The following functions' implementations are in RenderBlockLineLayout.cpp.
+    typedef std::pair<RenderText*, LazyLineBreakIterator> LineBreakIteratorInfo;
+    class LineBreaker {
+    public:
+        LineBreaker(RenderBlock* block)
+            : m_block(block)
+        {
+            reset();
+        }
+
+        InlineIterator nextLineBreak(InlineBidiResolver&, LineInfo&, LineBreakIteratorInfo&, FloatingObject* lastFloatFromPreviousLine, unsigned consecutiveHyphenatedLines);
+
+        bool lineWasHyphenated() { return m_hyphenated; }
+        const Vector<RenderBox*>& positionedObjects() { return m_positionedObjects; }
+        EClear clear() { return m_clear; }
+    private:
+        void reset();
+        
+        void skipTrailingWhitespace(InlineIterator&, const LineInfo&);
+        void skipLeadingWhitespace(InlineBidiResolver&, LineInfo&, FloatingObject* lastFloatFromPreviousLine, LineWidth&);
+        
+        RenderBlock* m_block;
+        bool m_hyphenated;
+        EClear m_clear;
+        Vector<RenderBox*> m_positionedObjects;
+    };
+
+    void checkFloatsInCleanLine(RootInlineBox*, Vector<FloatWithRect>&, size_t& floatIndex, bool& encounteredNewFloat, bool& dirtiedByFloat);
+    RootInlineBox* determineStartPosition(LineLayoutState&, InlineBidiResolver&);
+    void determineEndPosition(LineLayoutState&, RootInlineBox* startBox, InlineIterator& cleanLineStart, BidiStatus& cleanLineBidiStatus);
+    bool matchedEndLine(LineLayoutState&, const InlineBidiResolver&, const InlineIterator& endLineStart, const BidiStatus& endLineStatus);
+    bool checkPaginationAndFloatsAtEndLine(LineLayoutState&);
+    
+    RootInlineBox* constructLine(BidiRunList<BidiRun>&, const LineInfo&);
+    InlineFlowBox* createLineBoxes(RenderObject*, const LineInfo&, InlineBox* childBox);
+
+    void setMarginsForRubyRun(BidiRun*, RenderRubyRun*, RenderObject*, const LineInfo&);
+
+    void computeInlineDirectionPositionsForLine(RootInlineBox*, const LineInfo&, BidiRun* firstRun, BidiRun* trailingSpaceRun, bool reachedEnd, GlyphOverflowAndFallbackFontsMap&, VerticalPositionCache&);
+    void computeBlockDirectionPositionsForLine(RootInlineBox*, BidiRun*, GlyphOverflowAndFallbackFontsMap&, VerticalPositionCache&);
+    void deleteEllipsisLineBoxes();
+    void checkLinesForTextOverflow();
+
+    // Positions new floats and also adjust all floats encountered on the line if any of them
+    // have to move to the next page/column.
+    bool positionNewFloatOnLine(FloatingObject* newFloat, FloatingObject* lastFloatFromPreviousLine, LineInfo&, LineWidth&);
+    void appendFloatingObjectToLastLine(FloatingObject*);
+
+    // End of functions defined in RenderBlockLineLayout.cpp.
+
+    void paintFloats(PaintInfo&, const LayoutPoint&, bool preservePhase = false);
+    void paintContents(PaintInfo&, const LayoutPoint&);
+    void paintColumnContents(PaintInfo&, const LayoutPoint&, bool paintFloats = false);
+    void paintColumnRules(PaintInfo&, const LayoutPoint&);
+    void paintChildren(PaintInfo&, const LayoutPoint&);
+    void paintEllipsisBoxes(PaintInfo&, const LayoutPoint&);
+    void paintSelection(PaintInfo&, const LayoutPoint&);
+    void paintCaret(PaintInfo&, const LayoutPoint&, CaretType);
+
+    FloatingObject* insertFloatingObject(RenderBox*);
+    void removeFloatingObject(RenderBox*);
+    void removeFloatingObjectsBelow(FloatingObject*, int logicalOffset);
+    
+    // Called from lineWidth, to position the floats added in the last line.
+    // Returns true if and only if it has positioned any floats.
+    bool positionNewFloats();
+
+    bool hasPositionedFloats() const { return m_hasPositionedFloats; }
+    void addPositionedFloats();
+    bool positionedFloatsNeedRelayout();
+
+    void clearFloats(BlockLayoutPass);
+    LayoutUnit getClearDelta(RenderBox* child, LayoutUnit yPos);
+
+    virtual bool avoidsFloats() const;
+
+    bool hasOverhangingFloats() { return parent() && !hasColumns() && containsFloats() && lowestFloatLogicalBottomIncludingPositionedFloats() > logicalHeight(); }
+    bool hasOverhangingFloat(RenderBox*);
+    void addIntrudingFloats(RenderBlock* prev, LayoutUnit xoffset, LayoutUnit yoffset);
+    LayoutUnit addOverhangingFloats(RenderBlock* child, bool makeChildPaintOtherFloats);
+
+    LayoutUnit lowestFloatLogicalBottom() const { return lowestFloatLogicalBottom(FloatingObject::FloatLeftRight); }
+    LayoutUnit lowestFloatLogicalBottomIncludingPositionedFloats() const { return lowestFloatLogicalBottom(FloatingObject::FloatAll); }
+    LayoutUnit lowestFloatLogicalBottom(FloatingObject::Type) const;
+    LayoutUnit nextFloatLogicalBottomBelow(LayoutUnit) const;
+    
+    virtual bool hitTestColumns(const HitTestRequest&, HitTestResult&, const LayoutPoint& pointInContainer, const LayoutPoint& accumulatedOffset, HitTestAction);
+    virtual bool hitTestContents(const HitTestRequest&, HitTestResult&, const LayoutPoint& pointInContainer, const LayoutPoint& accumulatedOffset, HitTestAction);
+    bool hitTestFloats(const HitTestRequest&, HitTestResult&, const LayoutPoint& pointInContainer, const LayoutPoint& accumulatedOffset);
+
+    virtual bool isPointInOverflowControl(HitTestResult&, const LayoutPoint& pointInContainer, const LayoutPoint& accumulatedOffset);
+
+    void computeInlinePreferredLogicalWidths();
+    void computeBlockPreferredLogicalWidths();
+
+    // Obtains the nearest enclosing block (including this block) that contributes a first-line style to our inline
+    // children.
+    virtual RenderBlock* firstLineBlock() const;
+
+    virtual LayoutRect rectWithOutlineForRepaint(RenderBoxModelObject* repaintContainer, LayoutUnit outlineWidth) const;
+    virtual RenderStyle* outlineStyleForRepaint() const;
+    
+    virtual RenderObject* hoverAncestor() const;
+    virtual void updateDragState(bool dragOn);
+    virtual void childBecameNonInline(RenderObject* child);
+
+    virtual LayoutRect selectionRectForRepaint(RenderBoxModelObject* repaintContainer, bool /*clipToVisibleContent*/)
+    {
+        return selectionGapRectsForRepaint(repaintContainer);
+    }
+    virtual bool shouldPaintSelectionGaps() const;
+    bool isSelectionRoot() const;
+    GapRects selectionGaps(RenderBlock* rootBlock, const LayoutPoint& rootBlockPhysicalPosition, const LayoutSize& offsetFromRootBlock,
+                           LayoutUnit& lastLogicalTop, LayoutUnit& lastLogicalLeft, LayoutUnit& lastLogicalRight, const PaintInfo* = 0);
+    GapRects inlineSelectionGaps(RenderBlock* rootBlock, const LayoutPoint& rootBlockPhysicalPosition, const LayoutSize& offsetFromRootBlock,
+                                 LayoutUnit& lastLogicalTop, LayoutUnit& lastLogicalLeft, LayoutUnit& lastLogicalRight, const PaintInfo*);
+    GapRects blockSelectionGaps(RenderBlock* rootBlock, const LayoutPoint& rootBlockPhysicalPosition, const LayoutSize& offsetFromRootBlock,
+                                LayoutUnit& lastLogicalTop, LayoutUnit& lastLogicalLeft, LayoutUnit& lastLogicalRight, const PaintInfo*);
+    LayoutRect blockSelectionGap(RenderBlock* rootBlock, const LayoutPoint& rootBlockPhysicalPosition, const LayoutSize& offsetFromRootBlock,
+                                 LayoutUnit lastLogicalTop, LayoutUnit lastLogicalLeft, LayoutUnit lastLogicalRight, LayoutUnit logicalBottom, const PaintInfo*);
+    LayoutUnit logicalLeftSelectionOffset(RenderBlock* rootBlock, LayoutUnit position);
+    LayoutUnit logicalRightSelectionOffset(RenderBlock* rootBlock, LayoutUnit position);
+    
+    virtual void absoluteRects(Vector<LayoutRect>&, const LayoutPoint& accumulatedOffset) const;
+    virtual void absoluteQuads(Vector<FloatQuad>&, bool* wasFixed) const;
+
+    LayoutUnit desiredColumnWidth() const;
+    unsigned desiredColumnCount() const;
+
+    void paintContinuationOutlines(PaintInfo&, const LayoutPoint&);
+
+    virtual LayoutRect localCaretRect(InlineBox*, int caretOffset, LayoutUnit* extraWidthToEndOfLine = 0);
+
+    void adjustPointToColumnContents(LayoutPoint&) const;
+    void adjustForBorderFit(LayoutUnit x, LayoutUnit& left, LayoutUnit& right) const; // Helper function for borderFitAdjust
+
+    void markLinesDirtyInBlockRange(LayoutUnit logicalTop, LayoutUnit logicalBottom, RootInlineBox* highest = 0);
+
+    void newLine(EClear);
+
+    Position positionForBox(InlineBox*, bool start = true) const;
+    VisiblePosition positionForPointWithInlineChildren(const LayoutPoint&);
+
+    // Adjust from painting offsets to the local coords of this renderer
+    void offsetForContents(LayoutPoint&) const;
+
+    virtual void calcColumnWidth();
+    bool layoutColumns(bool hasSpecifiedPageLogicalHeight, LayoutUnit pageLogicalHeight, LayoutStateMaintainer&);
+    void makeChildrenAnonymousColumnBlocks(RenderObject* beforeChild, RenderBlock* newBlockBox, RenderObject* newChild);
+
+    bool expandsToEncloseOverhangingFloats() const;
+
+    void updateScrollInfoAfterLayout();
+
+    RenderObject* splitAnonymousBlocksAroundChild(RenderObject* beforeChild);
+    void splitBlocks(RenderBlock* fromBlock, RenderBlock* toBlock, RenderBlock* middleBlock,
+                     RenderObject* beforeChild, RenderBoxModelObject* oldCont);
+    void splitFlow(RenderObject* beforeChild, RenderBlock* newBlockBox,
+                   RenderObject* newChild, RenderBoxModelObject* oldCont);
+    RenderBlock* clone() const;
+    RenderBlock* continuationBefore(RenderObject* beforeChild);
+    RenderBlock* containingColumnsBlock(bool allowAnonymousColumnBlock = true);
+    RenderBlock* columnsBlockForSpanningElement(RenderObject* newChild);
+
+    class MarginInfo {
+        // Collapsing flags for whether we can collapse our margins with our children's margins.
+        bool m_canCollapseWithChildren : 1;
+        bool m_canCollapseMarginBeforeWithChildren : 1;
+        bool m_canCollapseMarginAfterWithChildren : 1;
+
+        // Whether or not we are a quirky container, i.e., do we collapse away top and bottom
+        // margins in our container.  Table cells and the body are the common examples. We
+        // also have a custom style property for Safari RSS to deal with TypePad blog articles.
+        bool m_quirkContainer : 1;
+
+        // This flag tracks whether we are still looking at child margins that can all collapse together at the beginning of a block.  
+        // They may or may not collapse with the top margin of the block (|m_canCollapseTopWithChildren| tells us that), but they will
+        // always be collapsing with one another.  This variable can remain set to true through multiple iterations 
+        // as long as we keep encountering self-collapsing blocks.
+        bool m_atBeforeSideOfBlock : 1;
+
+        // This flag is set when we know we're examining bottom margins and we know we're at the bottom of the block.
+        bool m_atAfterSideOfBlock : 1;
+
+        // These variables are used to detect quirky margins that we need to collapse away (in table cells
+        // and in the body element).
+        bool m_marginBeforeQuirk : 1;
+        bool m_marginAfterQuirk : 1;
+        bool m_determinedMarginBeforeQuirk : 1;
+
+        // These flags track the previous maximal positive and negative margins.
+        LayoutUnit m_positiveMargin;
+        LayoutUnit m_negativeMargin;
+
+    public:
+        MarginInfo(RenderBlock*, LayoutUnit beforeBorderPadding, LayoutUnit afterBorderPadding);
+
+        void setAtBeforeSideOfBlock(bool b) { m_atBeforeSideOfBlock = b; }
+        void setAtAfterSideOfBlock(bool b) { m_atAfterSideOfBlock = b; }
+        void clearMargin() { m_positiveMargin = m_negativeMargin = 0; }
+        void setMarginBeforeQuirk(bool b) { m_marginBeforeQuirk = b; }
+        void setMarginAfterQuirk(bool b) { m_marginAfterQuirk = b; }
+        void setDeterminedMarginBeforeQuirk(bool b) { m_determinedMarginBeforeQuirk = b; }
+        void setPositiveMargin(LayoutUnit p) { m_positiveMargin = p; }
+        void setNegativeMargin(LayoutUnit n) { m_negativeMargin = n; }
+        void setPositiveMarginIfLarger(LayoutUnit p)
+        {
+            if (p > m_positiveMargin)
+                m_positiveMargin = p;
+        }
+        void setNegativeMarginIfLarger(LayoutUnit n)
+        {
+            if (n > m_negativeMargin)
+                m_negativeMargin = n;
+        }
+
+        void setMargin(LayoutUnit p, LayoutUnit n) { m_positiveMargin = p; m_negativeMargin = n; }
+
+        bool atBeforeSideOfBlock() const { return m_atBeforeSideOfBlock; }
+        bool canCollapseWithMarginBefore() const { return m_atBeforeSideOfBlock && m_canCollapseMarginBeforeWithChildren; }
+        bool canCollapseWithMarginAfter() const { return m_atAfterSideOfBlock && m_canCollapseMarginAfterWithChildren; }
+        bool canCollapseMarginBeforeWithChildren() const { return m_canCollapseMarginBeforeWithChildren; }
+        bool canCollapseMarginAfterWithChildren() const { return m_canCollapseMarginAfterWithChildren; }
+        bool quirkContainer() const { return m_quirkContainer; }
+        bool determinedMarginBeforeQuirk() const { return m_determinedMarginBeforeQuirk; }
+        bool marginBeforeQuirk() const { return m_marginBeforeQuirk; }
+        bool marginAfterQuirk() const { return m_marginAfterQuirk; }
+        LayoutUnit positiveMargin() const { return m_positiveMargin; }
+        LayoutUnit negativeMargin() const { return m_negativeMargin; }
+        LayoutUnit margin() const { return m_positiveMargin - m_negativeMargin; }
+    };
+
+    void layoutBlockChild(RenderBox* child, MarginInfo&, LayoutUnit& previousFloatLogicalBottom, LayoutUnit& maxFloatLogicalBottom);
+    void adjustPositionedBlock(RenderBox* child, const MarginInfo&);
+    void adjustFloatingBlock(const MarginInfo&);
+    bool handleSpecialChild(RenderBox* child, const MarginInfo&);
+    bool handleFloatingChild(RenderBox* child, const MarginInfo&);
+    bool handlePositionedChild(RenderBox* child, const MarginInfo&);
+    bool handleRunInChild(RenderBox* child);
+    LayoutUnit collapseMargins(RenderBox* child, MarginInfo&);
+    LayoutUnit clearFloatsIfNeeded(RenderBox* child, MarginInfo&, LayoutUnit oldTopPosMargin, LayoutUnit oldTopNegMargin, LayoutUnit yPos);
+    LayoutUnit estimateLogicalTopPosition(RenderBox* child, const MarginInfo&, LayoutUnit& estimateWithoutPagination);
+    void determineLogicalLeftPositionForChild(RenderBox* child);
+    void handleAfterSideOfBlock(LayoutUnit top, LayoutUnit bottom, MarginInfo&);
+    void setCollapsedBottomMargin(const MarginInfo&);
+    // End helper functions and structs used by layoutBlockChildren.
+
+    // Helper function for layoutInlineChildren()
+    RootInlineBox* createLineBoxesFromBidiRuns(BidiRunList<BidiRun>&, const InlineIterator& end, LineInfo&, VerticalPositionCache&, BidiRun* trailingSpaceRun);
+    void layoutRunsAndFloats(LineLayoutState&, bool hasInlineChild);
+    void layoutRunsAndFloatsInRange(LineLayoutState&, InlineBidiResolver&, const InlineIterator& cleanLineStart, const BidiStatus& cleanLineBidiStatus, unsigned consecutiveHyphenatedLines);
+    void linkToEndLineIfNeeded(LineLayoutState&);
+    static void repaintDirtyFloats(Vector<FloatWithRect>& floats);
+
+protected:
+    // Pagination routines.
+    
+    // Returns the logicalOffset at the top of the next page. If the offset passed in is already at the top of the current page,
+    // then nextPageLogicalTop with ExcludePageBoundary will still move to the top of the next page. nextPageLogicalTop with
+    // IncludePageBoundary set will not.
+    //
+    // For a page height of 800px, the first rule will return 800 if the value passed in is 0. The second rule will simply return 0.
+    enum PageBoundaryRule { ExcludePageBoundary, IncludePageBoundary };
+    LayoutUnit nextPageLogicalTop(LayoutUnit logicalOffset, PageBoundaryRule = ExcludePageBoundary) const;
+    bool hasNextPage(LayoutUnit logicalOffset, PageBoundaryRule = ExcludePageBoundary) const;
+
+    LayoutUnit applyBeforeBreak(RenderBox* child, LayoutUnit logicalOffset); // If the child has a before break, then return a new yPos that shifts to the top of the next page/column.
+    LayoutUnit applyAfterBreak(RenderBox* child, LayoutUnit logicalOffset, MarginInfo&); // If the child has an after break, then return a new offset that shifts to the top of the next page/column.
+
+    LayoutUnit pageLogicalHeightForOffset(LayoutUnit offset) const;
+    LayoutUnit pageRemainingLogicalHeightForOffset(LayoutUnit offset, PageBoundaryRule = IncludePageBoundary) const;
+    bool pushToNextPageWithMinimumLogicalHeight(LayoutUnit& adjustment, LayoutUnit logicalOffset, LayoutUnit minimumLogicalHeight) const;
+
+    LayoutUnit adjustForUnsplittableChild(RenderBox* child, LayoutUnit logicalOffset, bool includeMargins = false); // If the child is unsplittable and can't fit on the current page, return the top of the next page/column.
+    void adjustLinePositionForPagination(RootInlineBox*, LayoutUnit& deltaOffset); // Computes a deltaOffset value that put a line at the top of the next page if it doesn't fit on the current page.
+    LayoutUnit adjustBlockChildForPagination(LayoutUnit logicalTopAfterClear, LayoutUnit estimateWithoutPagination, RenderBox* child, bool atBeforeSideOfBlock);
+
+    // This function is called to test a line box that has moved in the block direction to see if it has ended up in a new
+    // region/page/column that has a different available line width than the old one. Used to know when you have to dirty a
+    // line, i.e., that it can't be re-used.
+    bool lineWidthForPaginatedLineChanged(RootInlineBox*, LayoutUnit lineDelta = 0) const;
+
+    bool logicalWidthChangedInRegions() const;
+
+    virtual bool requiresColumns(int desiredColumnCount) const;
+
+public:
+    LayoutUnit offsetFromLogicalTopOfFirstPage() const;
+    RenderRegion* regionAtBlockOffset(LayoutUnit) const;
+    RenderRegion* clampToStartAndEndRegions(RenderRegion*) const;
+
+protected:
+    struct FloatingObjectHashFunctions {
+        static unsigned hash(FloatingObject* key) { return DefaultHash<RenderBox*>::Hash::hash(key->m_renderer); }
+        static bool equal(FloatingObject* a, FloatingObject* b) { return a->m_renderer == b->m_renderer; }
+        static const bool safeToCompareToEmptyOrDeleted = true;
+    };
+    struct FloatingObjectHashTranslator {
+        static unsigned hash(RenderBox* key) { return DefaultHash<RenderBox*>::Hash::hash(key); }
+        static bool equal(FloatingObject* a, RenderBox* b) { return a->m_renderer == b; }
+    };
+    typedef ListHashSet<FloatingObject*, 4, FloatingObjectHashFunctions> FloatingObjectSet;
+    typedef FloatingObjectSet::const_iterator FloatingObjectSetIterator;
+    typedef PODInterval<int, FloatingObject*> FloatingObjectInterval;
+    typedef PODIntervalTree<int, FloatingObject*> FloatingObjectTree;
+    typedef PODFreeListArena<PODRedBlackTree<FloatingObjectInterval>::Node> IntervalArena;
+    
+    template <FloatingObject::Type FloatTypeValue>
+    class FloatIntervalSearchAdapter {
+    public:
+        typedef FloatingObjectInterval IntervalType;
+        
+        FloatIntervalSearchAdapter(const RenderBlock* renderer, int value, LayoutUnit& offset, LayoutUnit* heightRemaining)
+            : m_renderer(renderer)
+            , m_value(value)
+            , m_offset(offset)
+            , m_heightRemaining(heightRemaining)
+        {
+        }
+        
+        inline int lowValue() const { return m_value; }
+        inline int highValue() const { return m_value; }
+        void collectIfNeeded(const IntervalType&) const;
+
+    private:
+        const RenderBlock* m_renderer;
+        int m_value;
+        LayoutUnit& m_offset;
+        LayoutUnit* m_heightRemaining;
+    };
+
+    class FloatingObjects {
+    public:
+        FloatingObjects(const RenderBlock* renderer, bool horizontalWritingMode)
+            : m_placedFloatsTree(UninitializedTree)
+            , m_leftObjectsCount(0)
+            , m_rightObjectsCount(0)
+            , m_positionedObjectsCount(0)
+            , m_horizontalWritingMode(horizontalWritingMode)
+            , m_renderer(renderer)
+        {
+        }
+
+        void clear();
+        void add(FloatingObject*);
+        void remove(FloatingObject*);
+        void addPlacedObject(FloatingObject*);
+        void removePlacedObject(FloatingObject*);
+        void setHorizontalWritingMode(bool b = true) { m_horizontalWritingMode = b; }
+
+        bool hasLeftObjects() const { return m_leftObjectsCount > 0; }
+        bool hasRightObjects() const { return m_rightObjectsCount > 0; }
+        bool hasPositionedObjects() const { return m_positionedObjectsCount > 0; }
+        const FloatingObjectSet& set() const { return m_set; }
+        const FloatingObjectTree& placedFloatsTree()
+        {
+            computePlacedFloatsTreeIfNeeded();
+            return m_placedFloatsTree; 
+        }
+    private:
+        void computePlacedFloatsTree();
+        inline void computePlacedFloatsTreeIfNeeded()
+        {
+            if (!m_placedFloatsTree.isInitialized())
+                computePlacedFloatsTree();
+        }
+        void increaseObjectsCount(FloatingObject::Type);
+        void decreaseObjectsCount(FloatingObject::Type);
+        FloatingObjectInterval intervalForFloatingObject(FloatingObject*);
+
+        FloatingObjectSet m_set;
+        FloatingObjectTree m_placedFloatsTree;
+        unsigned m_leftObjectsCount;
+        unsigned m_rightObjectsCount;
+        unsigned m_positionedObjectsCount;
+        bool m_horizontalWritingMode;
+        const RenderBlock* m_renderer;
+    };
+    OwnPtr<FloatingObjects> m_floatingObjects;
+    
+    typedef PositionedObjectsListHashSet::const_iterator Iterator;
+    OwnPtr<PositionedObjectsListHashSet> m_positionedObjects;
+
+    // Allocated only when some of these fields have non-default values
+    struct RenderBlockRareData {
+        WTF_MAKE_NONCOPYABLE(RenderBlockRareData); WTF_MAKE_FAST_ALLOCATED;
+    public:
+        RenderBlockRareData(const RenderBlock* block) 
+            : m_margins(positiveMarginBeforeDefault(block), negativeMarginBeforeDefault(block), positiveMarginAfterDefault(block), negativeMarginAfterDefault(block))
+            , m_paginationStrut(0)
+            , m_pageLogicalOffset(0)
+        { 
+        }
+
+        static LayoutUnit positiveMarginBeforeDefault(const RenderBlock* block)
+        { 
+            return std::max<LayoutUnit>(block->marginBefore(), 0);
+        }
+        
+        static LayoutUnit negativeMarginBeforeDefault(const RenderBlock* block)
+        { 
+            return std::max<LayoutUnit>(-block->marginBefore(), 0);
+        }
+        static LayoutUnit positiveMarginAfterDefault(const RenderBlock* block)
+        {
+            return std::max<LayoutUnit>(block->marginAfter(), 0);
+        }
+        static LayoutUnit negativeMarginAfterDefault(const RenderBlock* block)
+        {
+            return std::max<LayoutUnit>(-block->marginAfter(), 0);
+        }
+        
+        MarginValues m_margins;
+        int m_paginationStrut;
+        int m_pageLogicalOffset;
+     };
+
+    OwnPtr<RenderBlockRareData> m_rareData;
+
+    RenderObjectChildList m_children;
+    RenderLineBoxList m_lineBoxes;   // All of the root line boxes created for this block flow.  For example, <div>Hello<br>world.</div> will have two total lines for the <div>.
+
+    mutable signed m_lineHeight : 30;
+    bool m_beingDestroyed : 1;
+    bool m_hasPositionedFloats : 1;
+
+    // RenderRubyBase objects need to be able to split and merge, moving their children around
+    // (calling moveChildTo, moveAllChildrenTo, and makeChildrenNonInline).
+    friend class RenderRubyBase;
+    friend class LineWidth; // Needs to know FloatingObject
+
+private:
+    // Used to store state between styleWillChange and styleDidChange
+    static bool s_canPropagateFloatIntoSibling;
+};
+
+inline RenderBlock* toRenderBlock(RenderObject* object)
+{ 
+    ASSERT(!object || object->isRenderBlock());
+    return static_cast<RenderBlock*>(object);
+}
+
+inline const RenderBlock* toRenderBlock(const RenderObject* object)
+{ 
+    ASSERT(!object || object->isRenderBlock());
+    return static_cast<const RenderBlock*>(object);
+}
+
+// This will catch anyone doing an unnecessary cast.
+void toRenderBlock(const RenderBlock*);
+
+#ifndef NDEBUG
+// These structures are used by PODIntervalTree for debugging purposes.
+template <> struct ValueToString<int> {
+    static String string(const int value);
+};
+template<> struct ValueToString<RenderBlock::FloatingObject*> {
+    static String string(const RenderBlock::FloatingObject*);
+};
+#endif
+
+} // namespace WebCore
+
+#endif // RenderBlock_h