MacViews: Use RenderTextHarfBuzz only for Textfields

ui/gfx/render_text.h

 // Copyright (c) 2012 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_H_
 #define UI_GFX_RENDER_TEXT_H_
 
 #include <algorithm>
 #include <cstring>
 #include <string>
@@ skipping 173 matching lines @@
 // RenderText represents an abstract model of styled text and its corresponding
 // visual layout. Support is built in for a cursor, a selection, simple styling,
 // complex scripts, and bi-directional text. Implementations provide mechanisms
 // for rendering and translation between logical and visual data.
 class GFX_EXPORT RenderText {
  public:
   virtual ~RenderText();
 
   // Creates a platform-specific or cross-platform RenderText instance.
   static RenderText* CreateInstance();
+  static RenderText* CreateInstanceForEditing();
+
+  // Creates another instance of the same concrete class.
+  virtual scoped_ptr<RenderText> CreateInstanceOfSameType() const = 0;
 
   const base::string16& text() const { return text_; }
   void SetText(const base::string16& text);
 
   HorizontalAlignment horizontal_alignment() const {
     return horizontal_alignment_;
   }
   void SetHorizontalAlignment(HorizontalAlignment alignment);
 
   const FontList& font_list() const { return font_list_; }
@@ skipping 519 matching lines @@
   // Lines computed by EnsureLayout. These should be invalidated with
   // ResetLayout and on |display_rect_| changes.
   std::vector<internal::Line> lines_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderText);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RENDER_TEXT_H_