Enable HarfBuzz by default everywhere except CrOS

ui/gfx/render_text.cc

Index: ui/gfx/render_text.cc
diff --git a/ui/gfx/render_text.cc b/ui/gfx/render_text.cc
index d5d4011d8c08bd7dc86eb9d1f943cba32d79df52..4a0167e9e5a8969324a14b4f19ce38efa499ea30 100644
--- a/ui/gfx/render_text.cc
+++ b/ui/gfx/render_text.cc
@@ -393,16 +393,22 @@ 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) {