Switch to standard integer types in chrome/browser/, part 2 of 4.

chrome/browser/media/router/media_source.h

 // Copyright 2015 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_MEDIA_ROUTER_MEDIA_SOURCE_H_
 #define CHROME_BROWSER_MEDIA_ROUTER_MEDIA_SOURCE_H_
 
+#include <stddef.h>
+
 #include <ostream>
 #include <string>
 
 #include "base/hash.h"
 
 namespace media_router {
 
 
 class MediaSource {
  public:
@@ skipping 22 matching lines @@
     }
   };
 
  private:
   MediaSource::Id id_;
 };
 
 }  // namespace media_router
 
 #endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_SOURCE_H_