content: convert accessibility notifications to observer usage

content/public/browser/render_view_host_observer.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_PUBLIC_BROWSER_RENDER_VIEW_HOST_OBSERVER_H_
 #define CONTENT_PUBLIC_BROWSER_RENDER_VIEW_HOST_OBSERVER_H_
 
 #include "base/compiler_specific.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
@@ skipping 23 matching lines @@
 
   // Invoked when the RenderViewHost is being destroyed. Gives subclasses a
   // chance to cleanup.  The base implementation will delete the object.
   // |render_view_host| is passed as an argument since render_view_host() will
   // return NULL once this method enters.
   virtual void RenderViewHostDestroyed(RenderViewHost* render_view_host);
 
   // Notifies that a navigation is starting.
   virtual void Navigate(const GURL& url);
 
+  // Accessibility notifications.
+  virtual void AccessibilityLayoutComplete();

[dmazzoni, 2013/02/08 15:55:21]

Perhaps a single method with an argument would be cleaner?

  OnAccessibilityNotification(AccessibilityNotification notification_type);

A reason I didn't do that before (one notification with the accessibility
notification enum in the details) was so I could use
WindowedNotificationObserver.

+  virtual void AccessibilityLoadComplete();
+
   // IPC::Listener implementation.
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
 
   // IPC::Sender implementation.
   virtual bool Send(IPC::Message* message) OVERRIDE;
 
   RenderViewHost* render_view_host() const;
   int routing_id() { return routing_id_; }
 
  private:
   friend class RenderViewHostImpl;
 
   // Invoked from RenderViewHost. Invokes RenderViewHostDestroyed and NULL out
   // |render_view_host_|.
   void RenderViewHostDestruction();
 
   RenderViewHostImpl* render_view_host_;
 
   // The routing ID of the associated RenderViewHost.
   int routing_id_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderViewHostObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_RENDER_VIEW_HOST_OBSERVER_H_