Allow proper highlighting on universal overflow scroll.

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 149 matching lines @@
 
     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;

[Ian Vollick, 2014/06/13 17:07:49]

This change will need approval from someone familiar with this code.

     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;
 
     LayoutRect logicalRectToPhysicalRect(const LayoutPoint& physicalPosition, const LayoutRect& logicalRect);
 
@@ skipping 231 matching lines @@
     virtual RenderStyle* outlineStyleForPaintInvalidation() const OVERRIDE FINAL;
 
     virtual RenderObject* hoverAncestor() const OVERRIDE FINAL;
     virtual void updateDragState(bool dragOn) OVERRIDE FINAL;
     virtual void childBecameNonInline(RenderObject* child) OVERRIDE FINAL;
 
     virtual LayoutRect selectionRectForPaintInvalidation(const RenderLayerModelObject* paintInvalidationContainer, bool /*clipToVisibleContent*/) OVERRIDE FINAL
     {
         return selectionGapRectsForRepaint(paintInvalidationContainer);
     }
-    virtual bool shouldPaintSelectionGaps() const OVERRIDE FINAL;
     bool isSelectionRoot() const;
     GapRects selectionGaps(RenderBlock* rootBlock, const LayoutPoint& rootBlockPhysicalPosition, const LayoutSize& offsetFromRootBlock,
                            LayoutUnit& lastLogicalTop, LayoutUnit& lastLogicalLeft, LayoutUnit& lastLogicalRight, const PaintInfo* = 0);
     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*);
     virtual LayoutUnit logicalLeftSelectionOffset(RenderBlock* rootBlock, LayoutUnit position);
     virtual LayoutUnit logicalRightSelectionOffset(RenderBlock* rootBlock, LayoutUnit position);
 
@@ skipping 119 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 WebCore
 
 #endif // RenderBlock_h