Modify ALLOW_UNUSED to allow enabling unused local warnings on MSVC.

ppapi/proxy/dispatch_reply_message.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.
 
 // This file provides infrastructure for dispatching messasges from host
 // resource, inlcuding reply messages or unsolicited replies. Normal IPC Reply
 // handlers can't take extra parameters. We want to take a
 // ResourceMessageReplyParams as a parameter.
 
 #ifndef PPAPI_PROXY_DISPATCH_REPLY_MESSAGE_H_
@@ skipping 116 matching lines @@
       << "Resource reply message of unexpected type.";
   (obj->*method)(reply_params);
 }
 
 // When using PPAPI_DISPATCH_PLUGIN_RESOURCE_CALL* below, use this macro to
 // begin the map instead of IPC_BEGIN_MESSAGE_MAP. The reason is that the macros
 // in src/ipc are all closely tied together, and there might be errors for
 // unused variables or other errors if they're used with these macros.
 #define PPAPI_BEGIN_MESSAGE_MAP(class_name, msg) \
   { \
-    typedef class_name _IpcMessageHandlerClass ALLOW_UNUSED; \
+    typedef class_name _IpcMessageHandlerClass ALLOW_UNUSED_TYPE; \
     const IPC::Message& ipc_message__ = msg; \
     switch (ipc_message__.type()) { \
 
 // Note that this only works for message with 1 or more parameters. For
 // 0-parameter messages you need to use the _0 version below (since there are
 // no params in the message).
 #define PPAPI_DISPATCH_PLUGIN_RESOURCE_CALL(msg_class, member_func) \
     case msg_class::ID: { \
       msg_class::Schema::Param p; \
       if (msg_class::Read(&ipc_message__, &p)) { \
@@ skipping 20 matching lines @@
     break;
 
 #define PPAPI_END_MESSAGE_MAP() \
   } \
 }
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_DISPATCH_REPLY_MESSAGE_H_