Improving direction-based selection strategy.

Source/core/editing/FrameSelection.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 109 matching lines @@
 
     SelectionType selectionType() const { return m_selection.selectionType(); }
 
     EAffinity affinity() const { return m_selection.affinity(); }
 
     bool modify(EAlteration, SelectionDirection, TextGranularity, EUserTriggered = NotUserTriggered);
     enum VerticalDirection { DirectionUp, DirectionDown };
     bool modify(EAlteration, unsigned verticalDistance, VerticalDirection, EUserTriggered = NotUserTriggered, CursorAlignOnScroll = AlignCursorOnScrollIfNeeded);
 
     // Moves the selection extent based on the selection granularity strategy.
-    // This function does not allow the selection to collapse. If the new extent
-    // is set to the same position as the current base, this function will do
-    // nothing.
-    void moveRangeSelectionExtent(const VisiblePosition&);
+    // This function does not allow the selection to collapse. If the new
+    // extent is resolved to the same position as the current base, this
+    // function will do nothing.
+    void moveRangeSelectionExtent(const IntPoint&);
     void moveRangeSelection(const VisiblePosition& base, const VisiblePosition& extent, TextGranularity);
 
     TextGranularity granularity() const { return m_granularity; }
 
     void setStart(const VisiblePosition &, EUserTriggered = NotUserTriggered);
     void setEnd(const VisiblePosition &, EUserTriggered = NotUserTriggered);
 
     void setBase(const VisiblePosition&, EUserTriggered = NotUserTriggered);
     void setExtent(const VisiblePosition&, EUserTriggered = NotUserTriggered);
 
@@ skipping 183 matching lines @@
 }
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showTree(const blink::FrameSelection&);
 void showTree(const blink::FrameSelection*);
 #endif
 
 #endif // FrameSelection_h