Consolidate message observer API for win and aura (and touch).

base/message_loop.h

 // 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.
 
 #ifndef BASE_MESSAGE_LOOP_H_
 #define BASE_MESSAGE_LOOP_H_
 #pragma once
 
 #include <queue>
 #include <string>
@@ skipping 66 matching lines @@
 //   MessageLoop::current()->SetNestableTasksAllowed(old_state);
 //   // Process hr  (the result returned by DoDragDrop().
 //
 // Please be SURE your task is reentrant (nestable) and all global variables
 // are stable and accessible before calling SetNestableTasksAllowed(true).
 //
 class BASE_EXPORT MessageLoop : public base::MessagePump::Delegate {
  public:
 #if defined(OS_WIN)
   typedef base::MessagePumpWin::Dispatcher Dispatcher;
-  typedef base::MessagePumpForUI::Observer Observer;
+  typedef base::MessagePumpObserver Observer;
 #elif !defined(OS_MACOSX) && !defined(OS_ANDROID)
   typedef base::MessagePumpDispatcher Dispatcher;
   typedef base::MessagePumpObserver Observer;
 #endif
 
   // A MessageLoop has a particular type, which indicates the set of
   // asynchronous events it may process in addition to tasks and timers.
   //
   // TYPE_DEFAULT
   //   This type of ML only supports tasks and timers.
@@ skipping 608 matching lines @@
 #endif  // defined(OS_POSIX)
 };
 
 // Do not add any member variables to MessageLoopForIO!  This is important b/c
 // MessageLoopForIO is often allocated via MessageLoop(TYPE_IO).  Any extra
 // data that you need should be stored on the MessageLoop's pump_ instance.
 COMPILE_ASSERT(sizeof(MessageLoop) == sizeof(MessageLoopForIO),
                MessageLoopForIO_should_not_have_extra_member_variables);
 
 #endif  // BASE_MESSAGE_LOOP_H_