Add multiline support to RenderTextHarfBuzz.

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 95 matching lines @@
   std::vector<Rect> GetSubstringBounds(const Range& range) override;
   size_t TextIndexToLayoutIndex(size_t index) const override;
   size_t LayoutIndexToTextIndex(size_t index) const override;
   bool IsValidCursorIndex(size_t index) override;
   void ResetLayout() override;
   void EnsureLayout() override;
   void DrawVisualText(Canvas* canvas) override;
 
  private:
   friend class RenderTextTest;
+  FRIEND_TEST_ALL_PREFIXES(RenderTextTest, Multiline_NormalWidth);
   FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_RunDirection);
   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);
 
+  // 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(uint8 test_width) {
+    glyph_width_for_test_ = test_width;
+  }
+
   // 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 GetRunContainingXCoord(float x, float* offset) 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(
       const internal::TextRunHarfBuzz* run);
@@ skipping 27 matching lines @@
   // 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_;
 
   bool needs_layout_;
 
   // ICU grapheme iterator for the layout text. Valid when |!needs_layout_|. Can
   // be NULL in case of an error.
   scoped_ptr<base::i18n::BreakIterator> grapheme_iterator_;
 
+  // The total size of the layouted text.
+  SizeF total_size_;
+
+  // Fixed width of glyphs. This should only be set in test environments.
+  uint8 glyph_width_for_test_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderTextHarfBuzz);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RENDER_TEXT_HARFBUZZ_H_