Cleanup: Remove unneeded forward declarations from various chrome/browser subdirectories.

chrome/browser/notifications/notification_object_proxy.h

Index: chrome/browser/notifications/notification_object_proxy.h
===================================================================
--- chrome/browser/notifications/notification_object_proxy.h	(revision 109953)
+++ chrome/browser/notifications/notification_object_proxy.h	(working copy)
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -10,11 +10,6 @@
 
 #include "chrome/browser/notifications/notification_delegate.h"
 
-class MessageLoop;
-namespace IPC {
-class Message;
-}
-
 // A NotificationObjectProxy stands in for the JavaScript Notification object
 // which corresponds to a notification toast on the desktop.  It can be signaled
 // when various events occur regarding the desktop notification, and the