Use macros to define pepper interfaces

ppapi/proxy/ppb_var_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_PPB_VAR_PROXY_H_
 #define PPAPI_PPB_VAR_PROXY_H_
 
 #include "ppapi/proxy/interface_proxy.h"
 
 struct PPB_Var;
 
 namespace ppapi {
 namespace proxy {
 
-class PPB_Var_Proxy : public InterfaceProxy {
- public:
-  PPB_Var_Proxy(Dispatcher* dispatcher,
-                const void* target_interface);
-  virtual ~PPB_Var_Proxy();
-
-  static const Info* GetInfo();
-
-  const PPB_Var* ppb_var_target() const {
-    return static_cast<const PPB_Var*>(target_interface());
-  }
-
-  // InterfaceProxy implementation. In this case, no messages are sent or
-  // received, so this always returns false.
-  virtual bool OnMessageReceived(const IPC::Message& msg);
-
-};
+// Returns a pointer to the plugin-specific implementation of PPB_Var.
+// There is no proxy object since this is implemented entirely in-process.
+const PPB_Var* GetPPB_Var_Interface();
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PPB_VAR_PROXY_H_