Add VectorIconButton functionality to ImageButton.

ui/message_center/views/message_center_button_bar.h

Index: ui/message_center/views/message_center_button_bar.h
diff --git a/ui/message_center/views/message_center_button_bar.h b/ui/message_center/views/message_center_button_bar.h
index 41b40187a52a80ec3a3643e1d2ea08de0a46bdbd..4b9176c335fcb3322ccf85fc162904e3cd4280e0 100644
--- a/ui/message_center/views/message_center_button_bar.h
+++ b/ui/message_center/views/message_center_button_bar.h
@@ -8,7 +8,6 @@
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "ui/message_center/message_center_export.h"
-#include "ui/views/controls/button/button.h"
 #include "ui/views/controls/button/image_button.h"
 #include "ui/views/view.h"
 
@@ -26,7 +25,7 @@ class NotifierSettingsProvider;
 // MessageCenterButtonBar is the class that shows the content outside the main
 // notification area - the label (or NotifierGroup switcher) and the buttons.
 class MessageCenterButtonBar : public views::View,
-                               public views::ButtonListener {
+                               public views::ImageButtonDelegate {
  public:
   MessageCenterButtonBar(MessageCenterView* message_center_view,
                          MessageCenter* message_center,
@@ -59,10 +58,10 @@ class MessageCenterButtonBar : public views::View,
   // depending on the visibility of different parts of the button bar.
   void ViewVisibilityChanged();
 
-  // Overridden from views::View:
+  // views::View:
   void ChildVisibilityChanged(views::View* child) override;
 
-  // Overridden from views::ButtonListener:
+  // views::ImageButtonDelegate:
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
   MessageCenterView* message_center_view() const {