MacViews: Use RenderTextHarfBuzz only for Textfields

ui/gfx/render_text_pango.cc

 // 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.
 
 #include "ui/gfx/render_text_pango.h"
 
 #include <pango/pangocairo.h>
 #include <algorithm>
 #include <string>
 #include <vector>
@@ skipping 71 matching lines @@
       current_line_(NULL),
       log_attrs_(NULL),
       num_log_attrs_(0),
       layout_text_(NULL) {
 }
 
 RenderTextPango::~RenderTextPango() {
   ResetLayout();
 }
 
+scoped_ptr<RenderText> RenderTextPango::CreateInstanceOfSameType() const {
+  return scoped_ptr<RenderTextPango>(new RenderTextPango);
+}
+
 Size RenderTextPango::GetStringSize() {
   EnsureLayout();
   int width = 0, height = 0;
   pango_layout_get_pixel_size(layout_, &width, &height);
 
   // Pango returns 0 widths for very long strings (of 0x40000 chars or more).
   // This is caused by an int overflow in pango_glyph_string_extents_range.
   // Absurdly long strings may even report non-zero garbage values for width;
   // while detecting that isn't worthwhile, this handles the 0 width cases.
   const long kAbsurdLength = 100000;
@@ skipping 420 matching lines @@
                                           int glyph_index) const {
   return LayoutIndexToTextIndex(run->item->offset +
                                 run->glyphs->log_clusters[glyph_index]);
 }
 
 RenderText* RenderText::CreateNativeInstance() {
   return new RenderTextPango;
 }
 
 }  // namespace gfx