Update legacy Tuple-using code.

ppapi/proxy/ppapi_proxy_test.cc

 // 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.
 
 #include "ppapi/proxy/ppapi_proxy_test.h"
 
 #include <sstream>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 124 matching lines @@
       sink().GetUniqueMessageMatching(IPC_REPLY_ID);
   EXPECT_TRUE(reply_msg);
   if (!reply_msg)
     return false;
 
   TupleTypes<PpapiMsg_SupportsInterface::ReplyParam>::ValueTuple reply_data;
   EXPECT_TRUE(PpapiMsg_SupportsInterface::ReadReplyParam(
       reply_msg, &reply_data));
 
   sink().ClearMessages();
-  return reply_data.a;
+  return get<0>(reply_data);
 }
 
 // PluginProxyTestHarness ------------------------------------------------------
 
 PluginProxyTestHarness::PluginProxyTestHarness(
     GlobalsConfiguration globals_config)
     : globals_config_(globals_config) {
 }
 
 PluginProxyTestHarness::~PluginProxyTestHarness() {
@@ skipping 426 matching lines @@
   plugin_thread_.message_loop_proxy()->PostTask(FROM_HERE,
       base::Bind(&RunTaskOnRemoteHarness,
                  task,
                  &task_complete));
   task_complete.Wait();
 }
 
 
 }  // namespace proxy
 }  // namespace ppapi