fix know issues in RenderText

ui/gfx/render_text_linux.h

Index: ui/gfx/render_text_linux.h
===================================================================
--- ui/gfx/render_text_linux.h	(revision 100008)
+++ ui/gfx/render_text_linux.h	(working copy)
@@ -30,7 +30,9 @@
   virtual SelectionModel FindCursorPosition(const Point& point) OVERRIDE;
   virtual Rect GetCursorBounds(const SelectionModel& position,
                                bool insert_mode) OVERRIDE;
+  virtual size_t GetIndexOfNextGrapheme(size_t position) OVERRIDE;
 
+
  protected:
   // Overridden from RenderText:
   virtual SelectionModel GetLeftSelectionModel(const SelectionModel& current,
@@ -40,6 +42,7 @@
   virtual SelectionModel LeftEndSelectionModel() OVERRIDE;
   virtual SelectionModel RightEndSelectionModel() OVERRIDE;
   virtual size_t GetIndexOfPreviousGrapheme(size_t position) OVERRIDE;
+  virtual bool IsCursorablePosition(size_t position) OVERRIDE;
 
  private:
   enum RelativeLogicalPosition {
@@ -47,9 +50,6 @@
     NEXT
   };
 
-  // Get the logical start index of the next grapheme after |position|.
-  size_t GetIndexOfNextGrapheme(size_t position);
-
   // Returns the run that contains |position|. Return NULL if not found.
   GSList* GetRunContainingPosition(size_t position) const;