Cache gfx::RenderText instances in views::Label.

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 117 matching lines @@
 
 }  // namespace internal
 
 class GFX_EXPORT RenderTextHarfBuzz : public RenderText {
  public:
   RenderTextHarfBuzz();
   ~RenderTextHarfBuzz() override;
 
   // RenderText:
   scoped_ptr<RenderText> CreateInstanceOfSameType() const override;
+  bool MultilineSupported() const override;
   const base::string16& GetDisplayText() override;
   Size GetStringSize() override;
   SizeF GetStringSizeF() override;
   SelectionModel FindCursorPosition(const Point& point) override;
   std::vector<FontSpan> GetFontSpansForTesting() override;
   Range GetGlyphBounds(size_t index) override;
 
  protected:
   // RenderText:
   int GetDisplayTextBaseline() override;
@@ skipping 111 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_