fix know issues in RenderText

ui/gfx/render_text_win.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_GFX_RENDER_TEXT_WIN_H_
 #define UI_GFX_RENDER_TEXT_WIN_H_
 #pragma once
 
 #include <usp10.h>
 
@@ skipping 54 matching lines @@
                                bool insert_mode) OVERRIDE;
 
  protected:
   // Overridden from RenderText:
   virtual SelectionModel GetLeftSelectionModel(const SelectionModel& current,
                                                BreakType break_type) OVERRIDE;
   virtual SelectionModel GetRightSelectionModel(const SelectionModel& current,
                                                 BreakType break_type) OVERRIDE;
   virtual SelectionModel LeftEndSelectionModel() OVERRIDE;
   virtual SelectionModel RightEndSelectionModel() OVERRIDE;
-  virtual size_t GetIndexOfPreviousGrapheme(size_t position) OVERRIDE;
   virtual std::vector<Rect> GetSubstringBounds(size_t from, size_t to) OVERRIDE;
+  virtual bool IsCursorablePosition(size_t position) OVERRIDE;
 
  private:
+  virtual size_t IndexOfAdjacentGrapheme(size_t index, bool next) OVERRIDE;
+
   void ItemizeLogicalText();
   void LayoutVisualText(HDC hdc);
 
   // Return the run index that contains the argument; or the length of the
   // |runs_| vector if argument exceeds the text length or width.
   size_t GetRunContainingPosition(size_t position) const;
   size_t GetRunContainingPoint(const Point& point) const;
 
-  // Return an index belonging to the |next| or previous logical grapheme.
-  // The return value is bounded by 0 and the text length, inclusive.
-  size_t IndexOfAdjacentGrapheme(size_t index, bool next) const;
-
   // Given a |run|, returns the SelectionModel that contains the logical first
   // or last caret position inside (not at a boundary of) the run.
   // The returned value represents a cursor/caret position without a selection.
-  SelectionModel FirstSelectionModelInsideRun(internal::TextRun*) const;
-  SelectionModel LastSelectionModelInsideRun(internal::TextRun*) const;
+  SelectionModel FirstSelectionModelInsideRun(internal::TextRun*);
+  SelectionModel LastSelectionModelInsideRun(internal::TextRun*);
 
   // Get the selection model visually left/right of |selection| by one grapheme.
   // The returned value represents a cursor/caret position without a selection.
   SelectionModel LeftSelectionModel(const SelectionModel& selection);
   SelectionModel RightSelectionModel(const SelectionModel& selection);
 
   // Draw the text, cursor, and selection.
   void DrawSelection(Canvas* canvas);
   void DrawVisualText(Canvas* canvas);
   void DrawCursor(Canvas* canvas);
@@ skipping 14 matching lines @@
 
   scoped_array<int> visual_to_logical_;
   scoped_array<int> logical_to_visual_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderTextWin);
 };
 
 }  // namespace gfx;
 
 #endif  // UI_GFX_RENDER_TEXT_WIN_H_