Avoid extra FontRenderParams queries in 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 42 matching lines @@
   Range range;
   bool is_rtl;
   UBiDiLevel level;
   UScriptCode script;
 
   scoped_ptr<uint16[]> glyphs;
   scoped_ptr<SkPoint[]> positions;
   std::vector<uint32> glyph_to_char;
   size_t glyph_count;
 
+  std::string family;
   skia::RefPtr<SkTypeface> skia_face;
   FontRenderParams render_params;
   int font_size;
   int font_style;
   bool strike;
   bool diagonal_strike;
   bool underline;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TextRunHarfBuzz);
@@ skipping 47 matching lines @@
   // 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);
   SelectionModel LastSelectionModelInsideRun(
       const internal::TextRunHarfBuzz* run);
 
   // Break the text into logical runs and populate the visual <-> logical maps.
   void ItemizeText();
 
+  // Helper method for ShapeRun() that calls ShapeRunWithFont() with |run|,
+  // |family|, and |render_params|, returning true if the family provides all
+  // needed glyphs and false otherwise. Additionally updates |best_family|,
+  // |best_render_params|, and |best_missing_glyphs| if |family| has fewer than
+  // |best_missing_glyphs| missing glyphs.
+  bool CompareFamily(internal::TextRunHarfBuzz* run,
+                     const std::string& family,
+                     const gfx::FontRenderParams& render_params,
+                     std::string* best_family,
+                     gfx::FontRenderParams* best_render_params,
+                     size_t* best_missing_glyphs);
+
   // Shape the glyphs needed for the text |run|.
   void ShapeRun(internal::TextRunHarfBuzz* run);
   bool ShapeRunWithFont(internal::TextRunHarfBuzz* run,
-                        const std::string& font);
+                        const std::string& font_family,
+                        const FontRenderParams& params);
 
   // Text runs in logical order.
   ScopedVector<internal::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_;
 
   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_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderTextHarfBuzz);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RENDER_TEXT_HARFBUZZ_H_