Deleted OS_WIN and all Windows specific files from base.

base/threading/platform_thread_unittest.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 "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/platform_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-#if defined(OS_WIN)
-#include <windows.h>
-#endif
-
 namespace base {
 
 // Trivial tests that thread runs and doesn't crash on create and join ---------
 
 class TrivialThread : public PlatformThread::Delegate {
  public:
   TrivialThread() : did_run_(false) {}
 
   void ThreadMain() override { did_run_ = true; }
 
@@ skipping 241 matching lines @@
   }
 
   // Restore current thread priority for follow-up tests.
   PlatformThread::SetThreadPriority(current_handle, ThreadPriority::NORMAL);
 
   thread.MarkForTermination();
   PlatformThread::Join(handle);
 }
 
 }  // namespace base