Use macros to define pepper interfaces

ppapi/proxy/ppp_instance_private_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_INSTANCE_PRIVATE_PROXY_H_
 #define PPAPI_PROXY_PPP_INSTANCE_PRIVATE_PROXY_H_
 
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/pp_var.h"
 #include "ppapi/proxy/interface_proxy.h"
 #include "ppapi/shared_impl/host_resource.h"
 
 struct PPP_Instance_Private;
 
 namespace ppapi {
 namespace proxy {
 
 class SerializedVarReturnValue;
 
 class PPP_Instance_Private_Proxy : public InterfaceProxy {
  public:
-  PPP_Instance_Private_Proxy(Dispatcher* dispatcher,
-                             const void* target_interface);
+  PPP_Instance_Private_Proxy(Dispatcher* dispatcher);
   virtual ~PPP_Instance_Private_Proxy();
 
   static const Info* GetInfo();
 
-  const PPP_Instance_Private* ppp_instance_private_target() const {
-    return reinterpret_cast<const PPP_Instance_Private*>(target_interface());
-  }
-
  private:
   // InterfaceProxy implementation.
   virtual bool OnMessageReceived(const IPC::Message& msg);
 
   // Message handlers.
   void OnMsgGetInstanceObject(PP_Instance instance,
                               SerializedVarReturnValue result);
+
+  // When this proxy is in the plugin side, this value caches the interface
+  // pointer so we don't have to retrieve it from the dispatcher each time.
+  // In the host, this value is always NULL.
+  const PPP_Instance_Private* ppp_instance_private_impl_;
+
+  DISALLOW_COPY_AND_ASSIGN(PPP_Instance_Private_Proxy);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PPP_INSTANCE_PRIVATE_PROXY_H_