MacViews: Use RenderTextHarfBuzz only for Textfields

ui/gfx/render_text_harfbuzz.cc

 // 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.
 
 #include "ui/gfx/render_text_harfbuzz.h"
 
 #include <limits>
 #include <map>
 
 #include "base/i18n/bidi_line_iterator.h"
@@ skipping 570 matching lines @@
 }  // namespace internal
 
 RenderTextHarfBuzz::RenderTextHarfBuzz()
     : RenderText(),
       needs_layout_(false) {
   set_truncate_length(kMaxTextLength);
 }
 
 RenderTextHarfBuzz::~RenderTextHarfBuzz() {}
 
+scoped_ptr<RenderText> RenderTextHarfBuzz::NewInstance() const {
+  return scoped_ptr<RenderTextHarfBuzz>(new RenderTextHarfBuzz);
+}
+
 Size RenderTextHarfBuzz::GetStringSize() {
   const SizeF size_f = GetStringSizeF();
   return Size(std::ceil(size_f.width()), size_f.height());
 }
 
 SizeF RenderTextHarfBuzz::GetStringSizeF() {
   EnsureLayout();
   return lines()[0].size;
 }
 
@@ skipping 633 matching lines @@
     if (!run->render_params.subpixel_positioning)
       run->width = std::floor(run->width + 0.5f);
   }
 
   hb_buffer_destroy(buffer);
   hb_font_destroy(harfbuzz_font);
   return true;
 }
 
 }  // namespace gfx