Re-land RenderTextHarfBuzz: Decide run direction by BiDi embedding level

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 43 matching lines @@
   bool strike;
   bool diagonal_strike;
   bool underline;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TextRunHarfBuzz);
 };
 
 }  // namespace internal
 
-class RenderTextHarfBuzz : public RenderText {
+class GFX_EXPORT RenderTextHarfBuzz : public RenderText {
  public:
   RenderTextHarfBuzz();
   virtual ~RenderTextHarfBuzz();
 
   // Overridden from RenderText.
   virtual Size GetStringSize() OVERRIDE;
   virtual SelectionModel FindCursorPosition(const Point& point) OVERRIDE;
   virtual std::vector<FontSpan> GetFontSpansForTesting() OVERRIDE;
 
  protected:
   // Overridden from RenderText.
   virtual int GetLayoutTextBaseline() OVERRIDE;
   virtual SelectionModel AdjacentCharSelectionModel(
       const SelectionModel& selection,
       VisualCursorDirection direction) OVERRIDE;
   virtual SelectionModel AdjacentWordSelectionModel(
       const SelectionModel& selection,
       VisualCursorDirection direction) OVERRIDE;
   virtual Range GetGlyphBounds(size_t index) OVERRIDE;
   virtual std::vector<Rect> GetSubstringBounds(const Range& range) OVERRIDE;
   virtual size_t TextIndexToLayoutIndex(size_t index) const OVERRIDE;
   virtual size_t LayoutIndexToTextIndex(size_t index) const OVERRIDE;
   virtual bool IsValidCursorIndex(size_t index) OVERRIDE;
   virtual void ResetLayout() OVERRIDE;
   virtual void EnsureLayout() OVERRIDE;
   virtual void DrawVisualText(Canvas* canvas) OVERRIDE;
 
  private:
+  friend class RenderTextTest;
+  FRIEND_TEST_ALL_PREFIXES(RenderTextTest, HarfBuzz_RunDirection);
+
   // 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(int x, int* 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 14 matching lines @@
   std::vector<int32_t> logical_to_visual_;
 
   bool needs_layout_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderTextHarfBuzz);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RENDER_TEXT_HARFBUZZ_H_