RenderTextHarfBuzz: Allow mid-glyph cursors in multi-grapheme clusters

ui/gfx/render_text_harfbuzz.h

Index: ui/gfx/render_text_harfbuzz.h
diff --git a/ui/gfx/render_text_harfbuzz.h b/ui/gfx/render_text_harfbuzz.h
index 59ce92f21c31398eace9628103e883f332ace9f1..b96961595e884e432f4e813fcba23ae16d5a0a8e 100644
--- a/ui/gfx/render_text_harfbuzz.h
+++ b/ui/gfx/render_text_harfbuzz.h
@@ -5,6 +5,7 @@
 #ifndef UI_GFX_RENDER_TEXT_HARFBUZZ_H_
 #define UI_GFX_RENDER_TEXT_HARFBUZZ_H_
 
+#include "base/i18n/break_iterator.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "third_party/harfbuzz-ng/src/hb.h"
@@ -29,12 +30,17 @@ struct GFX_EXPORT TextRunHarfBuzz {
   // value is in run-space (0 corresponds to the first glyph in the run).
   Range CharRangeToGlyphRange(const Range& range) const;
 
+  // Writes the character and glyph ranges of the cluster containing |pos|.
+  void GetClusterAt(size_t pos, Range* chars, Range* glyphs) const;
+
+  // Returns bounds of the grapheme at |text_index|. Handles multi-grapheme

[msw, 2014/06/29 22:29:10]

nit: s/bounds of the grapheme/the grapheme bounds/ for a one-liner.

[ckocagil, 2014/07/24 21:46:56]

Done.

+  // glyphs.
+  Range GetGraphemeBounds(const base::string16& text, size_t text_index);
+
   // Returns whether the given shaped run contains any missing glyphs.
   bool HasMissingGlyphs() const;
 
-  // Returns the X coordinate of the leading or |trailing| edge of the glyph
-  // starting at |text_index|, relative to the left of the text (not the view).
-  int GetGlyphXBoundary(size_t text_index, bool trailing) const;
+  base::i18n::BreakIterator* GetGraphemeIterator(const base::string16& text);
 
   int width;
   int preceding_run_widths;
@@ -42,10 +48,11 @@ struct GFX_EXPORT TextRunHarfBuzz {
   bool is_rtl;
   UBiDiLevel level;
   UScriptCode script;
+  scoped_ptr<base::i18n::BreakIterator> grapheme_iterator;
 
   scoped_ptr<uint16[]> glyphs;
   scoped_ptr<SkPoint[]> positions;
-  scoped_ptr<uint32[]> glyph_to_char;
+  std::vector<uint32> glyph_to_char;
   size_t glyph_count;
 
   skia::RefPtr<SkTypeface> skia_face;