Use a layer transform for the waiting throbber

chrome/browser/ui/views/tabs/tab.h

Index: chrome/browser/ui/views/tabs/tab.h
diff --git a/chrome/browser/ui/views/tabs/tab.h b/chrome/browser/ui/views/tabs/tab.h
index 91c6a7cc9a5b2839323f4de6c5cc42d8e2a8d5ee..48d8dc7a7fab62bb65bfaac54daa78aae0a59308 100644
--- a/chrome/browser/ui/views/tabs/tab.h
+++ b/chrome/browser/ui/views/tabs/tab.h
@@ -160,6 +160,8 @@ class Tab : public gfx::AnimationDelegate,
   FRIEND_TEST_ALL_PREFIXES(TabStripTest, TabHitTestMaskWhenStacked);
   FRIEND_TEST_ALL_PREFIXES(TabStripTest, TabCloseButtonVisibilityWhenStacked);
 
+  class ThrobberView;
+
   // The animation object used to swap the favicon with the sad tab icon.
   class FaviconCrashAnimation;
   class TabCloseButton;
@@ -354,7 +356,7 @@ class Tab : public gfx::AnimationDelegate,
 
   scoped_refptr<gfx::AnimationContainer> animation_container_;
 
-  views::View* throbber_;
+  ThrobberView* throbber_;
   MediaIndicatorButton* media_indicator_button_;
   views::ImageButton* close_button_;
   views::Label* title_;