When accessing line boxes, use RenderBlockFlow instead of RenderBlock.

Source/core/rendering/RenderBlock.h

 /*
  * 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.
@@ skipping 63 matching lines @@
     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 OVERRIDE FINAL;
     virtual int baselinePosition(FontBaseline, bool firstLine, LineDirectionMode, LinePositionMode = PositionOnContainingLine) const OVERRIDE;
 
     LayoutUnit minLineHeightForReplacedRenderer(bool isFirstLine, LayoutUnit replacedHeight) const;
 
+protected:
     RenderLineBoxList* lineBoxes() { return &m_lineBoxes; }
 
     InlineFlowBox* firstLineBox() const { return m_lineBoxes.firstLineBox(); }
     InlineFlowBox* lastLineBox() const { return m_lineBoxes.lastLineBox(); }
 
+    RootInlineBox* firstRootBox() const { return static_cast<RootInlineBox*>(firstLineBox()); }
+    RootInlineBox* lastRootBox() const { return static_cast<RootInlineBox*>(lastLineBox()); }
+
+public:
     // FIXME-BLOCKFLOW: Remove virtualizaion when all callers have moved to RenderBlockFlow
     virtual void deleteLineBoxTree();
 
     virtual void addChild(RenderObject* newChild, RenderObject* beforeChild = 0) OVERRIDE;
     virtual void removeChild(RenderObject*) OVERRIDE;
 
     virtual void layoutBlock(bool relayoutChildren);
 
     void insertPositionedObject(RenderBox*);
     static void removePositionedObject(RenderBox*);
@@ skipping 46 matching lines @@
 
     // Block flows subclass availableWidth to handle multi column layout (shrinking the width available to children when laying out.)
     virtual LayoutUnit availableLogicalWidth() const OVERRIDE FINAL;
 
     LayoutPoint flipForWritingModeIncludingColumns(const LayoutPoint&) const;
     void adjustStartEdgeForWritingModeIncludingColumns(LayoutRect&) const;
 
     LayoutUnit blockDirectionOffset(const LayoutSize& offsetFromBlock) const;
     LayoutUnit inlineDirectionOffset(const LayoutSize& offsetFromBlock) const;
 
-    RootInlineBox* firstRootBox() const { return static_cast<RootInlineBox*>(firstLineBox()); }
-    RootInlineBox* lastRootBox() const { return static_cast<RootInlineBox*>(lastLineBox()); }
-
     virtual bool shouldPaintSelectionGaps() const OVERRIDE FINAL;
     GapRects selectionGapRectsForRepaint(const RenderLayerModelObject* 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);
     RenderBlock* blockBeforeWithinSelectionRoot(LayoutSize& offset) const;
 
     virtual void setSelectionState(SelectionState) OVERRIDE;
@@ skipping 352 matching lines @@
     // FIXME: This is temporary as we move code that accesses block flow
     // member variables out of RenderBlock and into RenderBlockFlow.
     friend class RenderBlockFlow;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderBlock, isRenderBlock());
 
 } // namespace blink
 
 #endif // RenderBlock_h