Add CaretBase::m_caretPainter, and compute caretBrowsing lazily.

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 129 matching lines @@
 
     void setBase(const VisiblePosition&, EUserTriggered = NotUserTriggered);
     void setExtent(const VisiblePosition&, EUserTriggered = NotUserTriggered);
 
     Position base() const { return m_selection.base(); }
     Position extent() const { return m_selection.extent(); }
     Position start() const { return m_selection.start(); }
     Position end() const { return m_selection.end(); }
 
     // Return the layoutObject that is responsible for painting the caret (in the selection start node)
-    LayoutBlock* caretLayoutObject() const;
+    LayoutBlock* caretLayoutObject() const { return CaretBase::caretPainter(); }
 
     // Bounds of (possibly transformed) caret in absolute coords
     IntRect absoluteCaretBounds();
 
     void didChangeFocus();
     void willBeModified(EAlteration, SelectionDirection);
 
     bool isNone() const { return m_selection.isNone(); }
     bool isCaret() const { return m_selection.isCaret(); }
     bool isRange() const { return m_selection.isRange(); }
@@ skipping 173 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