Move platform_thread to base/threading and put in the base namespace. I left ...

chrome/ppapi_plugin/ppapi_plugin_main.cc

 // Copyright (c) 2010 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 "base/message_loop.h"
+#include "base/threading/platform_thread.h"
 #include "build/build_config.h"
 #include "chrome/common/child_process.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/main_function_params.h"
 #include "chrome/ppapi_plugin/ppapi_thread.h"
 
 // Main function for starting the PPAPI plugin process.
 int PpapiPluginMain(const MainFunctionParams& parameters) {
   const CommandLine& command_line = parameters.command_line_;
   if (command_line.HasSwitch(switches::kPpapiStartupDialog)) {
     ChildProcess::WaitForDebugger(L"Ppapi");
   }
 
   MessageLoop main_message_loop(MessageLoop::TYPE_UI);
-  PlatformThread::SetName("CrPPAPIMain");
+  base::PlatformThread::SetName("CrPPAPIMain");
 
   ChildProcess ppapi_process;
   ppapi_process.set_main_thread(new PpapiThread());
 
   main_message_loop.Run();
   return 0;
 }