Allow Thread to initialize COM for Windows consumers who need it

base/threading/thread.h

 // 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.
 
-#ifndef BASE_THREAD_H_
-#define BASE_THREAD_H_
+#ifndef BASE_THREADING_THREAD_H_
+#define BASE_THREADING_THREAD_H_
 
 #include <string>
 
 #include "base/base_export.h"
 #include "base/message_loop.h"
 #include "base/message_loop_proxy.h"
 #include "base/threading/platform_thread.h"
 
 namespace base {
 
@@ skipping 163 matching lines @@
   // The name of the thread.  Used for debugging purposes.
   std::string name_;
 
   friend void ThreadQuitHelper();
 
   DISALLOW_COPY_AND_ASSIGN(Thread);
 };
 
 }  // namespace base
 
-#endif  // BASE_THREAD_H_
+#endif  // BASE_THREADING_THREAD_H_