Remove unneeded platform_thread.h includes. Reduces number of includes from 5...

chrome/browser/net/dns_master_unittest.cc

 // Copyright (c) 2006-2008 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 <time.h>
 
 #include <algorithm>
 #include <sstream>
 #include <string>
 
 #include "base/message_loop.h"
-#include "base/platform_thread.h"
 #include "base/scoped_ptr.h"
 #include "base/timer.h"
 #include "chrome/browser/net/dns_global.h"
 #include "chrome/browser/net/dns_host_info.h"
 #include "chrome/common/net/dns.h"
 #include "net/base/address_list.h"
 #include "net/base/host_resolver.h"
 #include "net/base/host_resolver_unittest.h"
 #include "net/base/winsock_init.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 506 matching lines @@
                                         recovered_referral_list));
   EXPECT_EQ(kLatencyNotFound,
             GetLatencyFromSerialization(motivation_hostname,
                                         img_subresource_hostname,
                                         recovered_referral_list));
 
   master.Shutdown();
 }
 
 }  // namespace chrome_browser_net