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

chrome/browser/geolocation/device_data_provider_unittest.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 "chrome/browser/geolocation/device_data_provider.h"
 
+#include "base/threading/platform_thread.h"
 #include "chrome/browser/geolocation/wifi_data_provider_common.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 class NullWifiDataListenerInterface
     : public WifiDataProviderCommon::ListenerInterface {
  public:
   // ListenerInterface
   virtual void DeviceDataUpdateAvailable(
       DeviceDataProvider<WifiData>* provider) {}
 };
 }
 
 TEST(GeolocationDeviceDataProviderWifiData, CreateDestroy) {
   // See http://crbug.com/59913 .  The main_message_loop is not required to be
   // run for correct behaviour, but we run it in this test to help smoke out
   // any race conditions between processing in the main loop and the setup /
   // tear down of the DeviceDataProvider thread.
   MessageLoopForUI main_message_loop;
   NullWifiDataListenerInterface listener;
   for (int i = 0; i < 10; i++) {
     DeviceDataProvider<WifiData>::Register(&listener);
     for (int j = 0; j < 10; j++) {
-      PlatformThread::Sleep(0);
+      base::PlatformThread::Sleep(0);
       main_message_loop.RunAllPending();  // See comment above
     }
     DeviceDataProvider<WifiData>::Unregister(&listener);
     for (int j = 0; j < 10; j++) {
-      PlatformThread::Sleep(0);
+      base::PlatformThread::Sleep(0);
       main_message_loop.RunAllPending();  // See comment above
     }
   }
 }