Add UpdateNotificationSize to MessageCenterController.

ui/message_center/views/custom_notification_view_unittest.cc

Index: ui/message_center/views/custom_notification_view_unittest.cc
diff --git a/ui/message_center/views/custom_notification_view_unittest.cc b/ui/message_center/views/custom_notification_view_unittest.cc
index 5c82693921e2299ab5a1bed9a91a22b2f0af1154..5ff8c0a9b75f39e2a6870dbb34f6b87a8a8c5a60 100644
--- a/ui/message_center/views/custom_notification_view_unittest.cc
+++ b/ui/message_center/views/custom_notification_view_unittest.cc
@@ -146,6 +146,11 @@ class TestMessageCenterController : public MessageCenterController {
     NOTREACHED();
   }
 
+  void ShouldUpdateNotification(const std::string& notification_id) override {
+    // For this test, this method should not be invoked.
+    NOTREACHED();
+  }
+
   bool IsRemoved(const std::string& notification_id) const {
     return (removed_ids_.find(notification_id) != removed_ids_.end());
   }