Revert 119198 - First pass at implementing the MessageLoop interface. This includes a simple

ppapi/proxy/ppb_message_loop_proxy.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 PPAPI_PROXY_PPB_MESSAGE_LOOP_PROXY_H_
-#define PPAPI_PROXY_PPB_MESSAGE_LOOP_PROXY_H_
-
-#include "base/basictypes.h"
-#include "ppapi/proxy/interface_proxy.h"
-
-struct PPB_MessageLoop_Dev_0_1;
-
-namespace ppapi {
-namespace proxy {
-
-class PPB_MessageLoop_Proxy : public InterfaceProxy {
- public:
-  PPB_MessageLoop_Proxy(Dispatcher* dispatcher);
-  virtual ~PPB_MessageLoop_Proxy();
-
-  static const PPB_MessageLoop_Dev_0_1* GetInterface();
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(PPB_MessageLoop_Proxy);
-};
-
-}  // namespace proxy
-}  // namespace ppapi
-
-#endif  // PPAPI_PROXY_PPB_MESSAGE_LOOP_PROXY_H_