Detect missing glyphs as returned by Vista in RenderTextWin.

ui/gfx/render_text_win.h

 // Copyright (c) 2012 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 91 matching lines @@
   const std::vector<Font>* GetLinkedFonts(const Font& font) const;
 
   // 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 GetRunContainingCaret(const SelectionModel& caret) const;
   size_t GetRunContainingPoint(const Point& point) 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* run);
-  SelectionModel LastSelectionModelInsideRun(internal::TextRun* run);
+  SelectionModel FirstSelectionModelInsideRun(const internal::TextRun* run);
+  SelectionModel LastSelectionModelInsideRun(const internal::TextRun* run);
+
+  // Returns a range [start, end) over the run's text corresponding to the given
+  // glyph index. For example, if the glyph covers characters "fi" in a run with
+  // text "hifi", then the returned range will have |start| == 2 and |end| == 4.
+  ui::Range GetTextRangeForRunGlyph(const internal::TextRun* run,
+                                    size_t glyph_index) const;
 
   // Cached HDC for performing Uniscribe API calls.
   static HDC cached_hdc_;
 
   // Cached map from font names to vectors of linked fonts.
   static std::map<std::string, std::vector<Font> > cached_linked_fonts_;
 
   SCRIPT_CONTROL script_control_;
   SCRIPT_STATE script_state_;
 
   std::vector<internal::TextRun*> runs_;
   Size string_size_;
 
   // A common vertical baseline for all the text runs. This is computed as the
   // largest baseline over all the runs' fonts.
   int common_baseline_;
 
   scoped_array<int> visual_to_logical_;
   scoped_array<int> logical_to_visual_;
 
   bool needs_layout_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderTextWin);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RENDER_TEXT_WIN_H_