Tab audio indicator: Use animation container on Mac

chrome/browser/ui/cocoa/tabs/tab_strip_controller.h

Index: chrome/browser/ui/cocoa/tabs/tab_strip_controller.h
diff --git a/chrome/browser/ui/cocoa/tabs/tab_strip_controller.h b/chrome/browser/ui/cocoa/tabs/tab_strip_controller.h
index b3cdcbecc826d141ce84cda3c4cfa3e0a46a47f8..dc5e357d7d8898c1e66ea23854bef80f24870e4a 100644
--- a/chrome/browser/ui/cocoa/tabs/tab_strip_controller.h
+++ b/chrome/browser/ui/cocoa/tabs/tab_strip_controller.h
@@ -27,6 +27,9 @@ class TabStripModel;
 namespace content {
 class WebContents;
 }
+namespace ui {
+class AnimationContainer;
+}
 
 // The interface for the tab strip controller's delegate.
 // Delegating TabStripModelObserverBridge's events (in lieu of directly
@@ -138,6 +141,8 @@ class WebContents;
 
   // Helper for performing tab selection as a result of dragging over a tab.
   scoped_ptr<HoverTabSelector> hoverTabSelector_;
+
+  scoped_refptr<ui::AnimationContainer> animationContainer_;
 }
 
 @property(nonatomic) CGFloat leftIndentForControls;