Add ability for a BubbleReference to update the BubbleUI.

components/bubble/bubble_delegate.h

Index: components/bubble/bubble_delegate.h
diff --git a/components/bubble/bubble_delegate.h b/components/bubble/bubble_delegate.h
index ebac50f33a3d5a4a56b7836d5acf225cfe9675b0..014b7d50c0b0bd844283ed4d8834422ef67e112c 100644
--- a/components/bubble/bubble_delegate.h
+++ b/components/bubble/bubble_delegate.h
@@ -27,6 +27,11 @@ class BubbleDelegate {
   // BubbleDelegate should not keep a reference to this newly created UI.
   virtual scoped_ptr<BubbleUI> BuildBubbleUI() = 0;
 
+  // Called to update an existing UI. This is the same BubbleUI that was created
+  // in |BuildBubbleUI|.
+  // Return true to indicate the UI was updated.
+  virtual bool UpdateBubbleUI(BubbleUI* bubble_ui);
+
  private:
   DISALLOW_COPY_AND_ASSIGN(BubbleDelegate);
 };