aura-x11: Install the dispatcher as a message-pump observer.

ui/aura/dispatcher_linux.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 UI_AURA_DISPATCHER_LINUX_H_
 #define UI_AURA_DISPATCHER_LINUX_H_
 #pragma once
 
 #include <map>
 #include <X11/Xlib.h>
 // Get rid of a macro from Xlib.h that conflicts with Aura's RootWindow class.
 #undef RootWindow
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/message_loop.h"
 
 namespace aura {
 
-class DispatcherLinux : public MessageLoop::Dispatcher {
+class DispatcherLinux : public MessageLoop::Dispatcher,
+                        public base::MessagePumpObserver {
  public:
   DispatcherLinux();
   virtual ~DispatcherLinux();
 
   void WindowDispatcherCreated(::Window window,
                                MessageLoop::Dispatcher* dispatcher);
   void WindowDispatcherDestroying(::Window window);
 
   // Overridden from MessageLoop::Dispatcher:
   virtual bool Dispatch(const base::NativeEvent& event) OVERRIDE;
 
+  // Overridden from base::MessagePumpObserver:
+  virtual base::EventStatus WillProcessEvent(
+      const base::NativeEvent& event) OVERRIDE;
+  virtual void DidProcessEvent(const base::NativeEvent& event) OVERRIDE;
+
  private:
   typedef std::map< ::Window, MessageLoop::Dispatcher* > DispatchersMap;
 
   MessageLoop::Dispatcher* GetDispatcherForXEvent(XEvent* xev) const;
 
   DispatchersMap dispatchers_;
 
   DISALLOW_COPY_AND_ASSIGN(DispatcherLinux);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_DISPATCHER_LINUX_H_