Create a new base/message_loop directory and move the message_loop_proxy.

base/message_loop_proxy_impl.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 BASE_MESSAGE_LOOP_PROXY_IMPL_H_
-#define BASE_MESSAGE_LOOP_PROXY_IMPL_H_
-
-#include "base/base_export.h"
-#include "base/message_loop.h"
-#include "base/message_loop_proxy.h"
-#include "base/synchronization/lock.h"
-
-namespace base {
-
-// A stock implementation of MessageLoopProxy that is created and managed by a
-// MessageLoop. For now a MessageLoopProxyImpl can only be created as part of a
-// MessageLoop.
-class BASE_EXPORT MessageLoopProxyImpl : public MessageLoopProxy {
- public:
-  // MessageLoopProxy implementation
-  virtual bool PostDelayedTask(const tracked_objects::Location& from_here,
-                               const base::Closure& task,
-                               base::TimeDelta delay) OVERRIDE;
-  virtual bool PostNonNestableDelayedTask(
-      const tracked_objects::Location& from_here,
-      const base::Closure& task,
-      base::TimeDelta delay) OVERRIDE;
-  virtual bool RunsTasksOnCurrentThread() const OVERRIDE;
-
- protected:
-  virtual ~MessageLoopProxyImpl();
-
-  // Override OnDestruct so that we can delete the object on the target message
-  // loop if it still exists.
-  virtual void OnDestruct() const OVERRIDE;
-
- private:
-  // Allow the MessageLoop to create a MessageLoopProxyImpl.
-  friend class ::MessageLoop;
-  friend class DeleteHelper<MessageLoopProxyImpl>;
-
-  MessageLoopProxyImpl();
-
-  // Called directly by MessageLoop::~MessageLoop.
-  virtual void WillDestroyCurrentMessageLoop();
-
-
-  bool PostTaskHelper(const tracked_objects::Location& from_here,
-                      const base::Closure& task,
-                      base::TimeDelta delay,
-                      bool nestable);
-
-  // The lock that protects access to target_message_loop_.
-  mutable base::Lock message_loop_lock_;
-  MessageLoop* target_message_loop_;
-
-  DISALLOW_COPY_AND_ASSIGN(MessageLoopProxyImpl);
-};
-
-}  // namespace base
-
-#endif  // BASE_MESSAGE_LOOP_PROXY_IMPL_H_