Correct multicol dirty rect for scrolled and flipped blocks writing mode.

third_party/WebKit/Source/core/layout/LayoutFlowThread.h

 /*
  * Copyright (C) 2011 Adobe Systems Incorporated. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above
  *    copyright notice, this list of conditions and the following
  *    disclaimer.
@@ skipping 99 matching lines @@
     // content as tall as |contentLogicalHeight|. |flowThreadOffset| is expected to be at the exact
     // top of a column that's known to not have enough space for |contentLogicalHeight|. This method
     // is called when the current column is too short to fit the content, in the hope that there
     // exists one that's tall enough further ahead. If no such column can be found,
     // |flowThreadOffset| will be returned.
     LayoutUnit nextLogicalTopForUnbreakableContent(LayoutUnit flowThreadOffset, LayoutUnit contentLogicalHeight) const;
 
     virtual bool isPageLogicalHeightKnown() const { return true; }
     bool pageLogicalSizeChanged() const { return m_pageLogicalSizeChanged; }
 
-    void collectLayerFragments(PaintLayerFragments&, const LayoutRect& layerBoundingBox, const LayoutRect& dirtyRectInFlowThread);
+    void collectLayerFragments(PaintLayerFragments&, const LayoutRect& layerBoundingBox, const LayoutRect& dirtyRectInMulticolContainer);
 
     // Return the visual bounding box based on the supplied flow-thread bounding box. Both
     // rectangles are completely physical in terms of writing mode.
     LayoutRect fragmentsBoundingBox(const LayoutRect& layerBoundingBox) const;
 
     // Convert a logical position in the flow thread coordinate space to a logical position in the
     // containing coordinate space.
     void flowThreadToContainingCoordinateSpace(LayoutUnit& blockPosition, LayoutUnit& inlinePosition) const;
 
     virtual LayoutPoint flowThreadPointToVisualPoint(const LayoutPoint& flowThreadPoint) const = 0;
@@ skipping 41 matching lines @@
 // These structures are used by PODIntervalTree for debugging.
 #ifndef NDEBUG
 template <> struct ValueToString<LayoutMultiColumnSet*> {
     static String toString(const LayoutMultiColumnSet* value) { return String::format("%p", value); }
 };
 #endif
 
 } // namespace blink
 
 #endif // LayoutFlowThread_h