Reland http://codereview.chromium.org/7292033

ppapi/c/ppp_messaging.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_C_PPP_MESSAGING_H_
 #define PPAPI_C_PPP_MESSAGING_H_
 
 #include "ppapi/c/pp_instance.h"
 
 struct PP_Var;
 
-#define PPP_MESSAGING_INTERFACE "PPP_Messaging;0.1"
+#define PPP_MESSAGING_INTERFACE_0_1 "PPP_Messaging;0.1"
+#define PPP_MESSAGING_INTERFACE_1_0 "PPP_Messaging;1.0"
+#define PPP_MESSAGING_INTERFACE PPP_MESSAGING_INTERFACE_1_0
 
 /**
  * @file
  * This file defines the PPP_Messaging interface containing pointers to
  * functions that you must implement to handle postMessage messages
  * on the associated DOM element.
  *
  */
 
 /** @addtogroup Interfaces
@@ skipping 38 matching lines @@
    * @endcode
    *
    */
   void (*HandleMessage)(PP_Instance instance, struct PP_Var message);
 };
 /**
  * @}
  */
 #endif  /* PPAPI_C_PPP_MESSAGING_H_ */