Convert the pp::proxy namespace to the ppapi::proxy namespace.

ppapi/proxy/ppp_messaging_proxy.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 PPAPI_PROXY_PPP_MESSAGING_PROXY_H_
 #define PPAPI_PROXY_PPP_MESSAGING_PROXY_H_
 
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/proxy/interface_proxy.h"
 
 struct PPP_Messaging;
 
-namespace pp {
+namespace ppapi {
 namespace proxy {
 
 class SerializedVarReceiveInput;
 
 class PPP_Messaging_Proxy : public InterfaceProxy {
  public:
   PPP_Messaging_Proxy(Dispatcher* dispatcher, const void* target_interface);
   virtual ~PPP_Messaging_Proxy();
 
   static const Info* GetInfo();
 
   const PPP_Messaging* ppp_messaging_target() const {
     return static_cast<const PPP_Messaging*>(target_interface());
   }
 
   // InterfaceProxy implementation.
   virtual bool OnMessageReceived(const IPC::Message& msg) OVERRIDE;
 
  private:
   // Message handlers.
   void OnMsgHandleMessage(PP_Instance instance,
                           SerializedVarReceiveInput data);
 };
 
 }  // namespace proxy
-}  // namespace pp
+}  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PPP_MESSAGING_PROXY_H_