Stop combining text runs which are connected by 'COMMON' blocks.

ui/gfx/render_text_harfbuzz.h

 // Copyright 2014 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_HARFBUZZ_H_
 #define UI_GFX_RENDER_TEXT_HARFBUZZ_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "third_party/harfbuzz-ng/src/hb.h"
@@ skipping 36 matching lines @@
   // Writes the character and glyph ranges of the cluster containing |pos|.
   void GetClusterAt(size_t pos, Range* chars, Range* glyphs) const;
 
   // Returns the grapheme bounds at |text_index|. Handles multi-grapheme glyphs.
   RangeF GetGraphemeBounds(base::i18n::BreakIterator* grapheme_iterator,
                            size_t text_index);
 
   // Returns whether the given shaped run contains any missing glyphs.
   bool HasMissingGlyphs() const;
 
+  // Returns the glyph width for the given character range. |char_range| is in
+  // text-space (0 corresponds to |GetDisplayText()[0]|).
+  SkScalar GetGlyphWidthForCharRange(const Range& char_range) const;
+
   float width;
   float preceding_run_widths;
   Range range;
   bool is_rtl;
   UBiDiLevel level;
   UScriptCode script;
 
   scoped_ptr<uint16[]> glyphs;
   scoped_ptr<SkPoint[]> positions;
   std::vector<uint32> glyph_to_char;
@@ skipping 41 matching lines @@
   // Initialize the index mapping.
   void InitIndexMap();
 
   // Precomputes the offsets for all runs.
   void ComputePrecedingRunWidths();
 
   // Get the total width of runs, as if they were shown on one line.
   // Do not use this when multiline is enabled.
   float width() const { return width_; }
 
+  // Get the run index applicable to |position| (at or preceeding |position|).
+  size_t GetRunIndexAt(size_t position) const;
+
  private:
   // Text runs in logical order.
   ScopedVector<TextRunHarfBuzz> runs_;
 
   // Maps visual run indices to logical run indices and vice versa.
   std::vector<int32_t> visual_to_logical_;
   std::vector<int32_t> logical_to_visual_;
 
   float width_;
 
@@ skipping 44 matching lines @@
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_HorizontalPositions);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest,
                            HarfBuzz_TextPositionWithFractionalSize);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_BreakRunsByUnicodeBlocks);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_BreakRunsByEmoji);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_SubglyphGraphemeCases);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_SubglyphGraphemePartition);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_NonExistentFont);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_UniscribeFallback);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_UnicodeFallback);
+  FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_LineBreakerBehavior);
+  FRIEND_TEST_ALL_PREFIXES(RenderTextTest,
+                           Multiline_SurrogatePairsOrCombiningChars);
+  FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_ZeroWidthChars);
 
   // Specify the width of a glyph for test. The width of glyphs is very
   // platform-dependent and environment-dependent. Otherwise multiline test
   // will become really flaky.
   void set_glyph_width_for_test(float test_width) {
     glyph_width_for_test_ = test_width;
   }
 
   // The actual implementation of the text drawing.
   void DrawVisualTextInternal(internal::SkiaTextRenderer* renderer);
@@ skipping 71 matching lines @@
 
   // Fixed width of glyphs. This should only be set in test environments.
   float glyph_width_for_test_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderTextHarfBuzz);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RENDER_TEXT_HARFBUZZ_H_