Move ExternalTabContainer into a directory with an OWNERS file.

chrome/browser/external_tab/external_tab_container_win.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 CHROME_BROWSER_EXTERNAL_TAB_CONTAINER_WIN_H_
-#define CHROME_BROWSER_EXTERNAL_TAB_CONTAINER_WIN_H_
+#ifndef CHROME_BROWSER_EXTERNAL_TAB_EXTERNAL_TAB_CONTAINER_WIN_H_
+#define CHROME_BROWSER_EXTERNAL_TAB_EXTERNAL_TAB_CONTAINER_WIN_H_
 #pragma once
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/lazy_instance.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 398 matching lines @@
     NOTREACHED();
     return false;
   }
 
   virtual void BeforeUnloadFired(content::WebContents* tab, bool proceed,
                                  bool* proceed_to_fire_unload) {
     NOTREACHED();
   }
 };
 
-#endif  // CHROME_BROWSER_EXTERNAL_TAB_CONTAINER_WIN_H_
+#endif  // CHROME_BROWSER_EXTERNAL_TAB_EXTERNAL_TAB_CONTAINER_WIN_H_