Enable HarfBuzz by default everywhere except CrOS

ui/gfx/render_text.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.h"
 
 #include <algorithm>
 #include <climits>
 
 #include "base/command_line.h"
@@ skipping 375 matching lines @@
   paint->setAutohinted(params.autohinter);
   paint->setHinting(FontRenderParamsHintingToSkPaintHinting(params.hinting));
 }
 
 }  // namespace internal
 
 RenderText::~RenderText() {
 }
 
 RenderText* RenderText::CreateInstance() {
-#if defined(OS_MACOSX) && defined(TOOLKIT_VIEWS)
-  // Use the more complete HarfBuzz implementation for Views controls on Mac.
-  return new RenderTextHarfBuzz;
+// Disable on Chrome OS. Blocked on http://crbug.com/423791
+#if defined(OS_CHROMEOS)
+  const bool default_is_harfbuzz = false;

[msw, 2014/10/15 20:09:57]

nit: these could just be return statements below the switch handling.

[ckocagil, 2014/10/15 20:17:30]

Done.

 #else
+  const bool default_is_harfbuzz = true;
+#endif
+
   if (CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableHarfBuzzRenderText)) {
     return new RenderTextHarfBuzz;
   }
-  return CreateNativeInstance();
-#endif
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableHarfBuzzRenderText)) {
+    return CreateNativeInstance();
+  }
+  return default_is_harfbuzz ? new RenderTextHarfBuzz : CreateNativeInstance();
 }
 
 void RenderText::SetText(const base::string16& text) {
   DCHECK(!composition_range_.IsValid());
   if (text_ == text)
     return;
   text_ = text;
 
   // Adjust ranged styles and colors to accommodate a new text length.
   // Clear style ranges as they might break new text graphemes and apply
@@ skipping 965 matching lines @@
   SetDisplayOffset(display_offset_.x() + delta_x);
 }
 
 void RenderText::DrawSelection(Canvas* canvas) {
   const std::vector<Rect> sel = GetSubstringBounds(selection());
   for (std::vector<Rect>::const_iterator i = sel.begin(); i < sel.end(); ++i)
     canvas->FillRect(*i, selection_background_focused_color_);
 }
 
 }  // namespace gfx