Introduce positionForPoint() in LocalFrame class as replacement of visiblePositionForPoint()

Source/core/editing/DragCaretController.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 26 matching lines @@
     static PassOwnPtrWillBeRawPtr<DragCaretController> create();
 
     LayoutBlock* caretLayoutObject() const;
     void paintDragCaret(LocalFrame*, GraphicsContext*, const LayoutPoint&, const LayoutRect& clipRect) const;
 
     bool isContentEditable() const { return m_position.rootEditableElement(); }
     bool isContentRichlyEditable() const;
 
     bool hasCaret() const { return m_position.isNotNull(); }
     const VisiblePosition& caretPosition() { return m_position; }
-    void setCaretPosition(const VisiblePosition&);
-    void clear() { setCaretPosition(VisiblePosition()); }
+    void setCaretPosition(const PositionWithAffinity&);
+    void clear() { setCaretPosition(PositionWithAffinity()); }
 
     void nodeWillBeRemoved(Node&);
 
     DECLARE_TRACE();
 
 private:
     DragCaretController();
 
     VisiblePosition m_position;
 };
 
 } // namespace blink
 
 #endif // DragCaretController_h