Pass a BubbleReference to BubbleUI::Show.

components/bubble/bubble_manager.h

Index: components/bubble/bubble_manager.h
diff --git a/components/bubble/bubble_manager.h b/components/bubble/bubble_manager.h
index 215441ae7db27515bb05c16c8173ac6c7213db10..931e74c97e53b8d7c9d89fe6b14ae4c6df4793f0 100644
--- a/components/bubble/bubble_manager.h
+++ b/components/bubble/bubble_manager.h
@@ -7,15 +7,12 @@
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
-#include "base/memory/weak_ptr.h"
 #include "base/threading/thread_checker.h"
 #include "components/bubble/bubble_close_reason.h"
+#include "components/bubble/bubble_reference.h"
 
-class BubbleController;
 class BubbleDelegate;
 
-typedef base::WeakPtr<BubbleController> BubbleReference;
-
 // Inherit from BubbleManager to show, update, and close bubbles.
 // Any class that inherits from BubbleManager should capture any events that
 // should dismiss a bubble or update its anchor point.