AesDecryptor callbacks now used in a thread-safe manner

media/cdm/aes_decryptor.h

 // Copyright 2013 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 MEDIA_CRYPTO_AES_DECRYPTOR_H_
 #define MEDIA_CRYPTO_AES_DECRYPTOR_H_
 
 #include <set>
 #include <string>
 
@@ skipping 117 matching lines @@
   // Keeps track of current valid session IDs.
   std::set<uint32> valid_sessions_;
 
   // Make web session ID unique per renderer by making it static. Web session
   // IDs seen by the app will be "1", "2", etc.
   static uint32 next_web_session_id_;
 
   NewKeyCB new_audio_key_cb_;
   NewKeyCB new_video_key_cb_;
 
+  // Protect |new_audio_key_cb_| and |new_video_key_cb_| as they are set on the
+  // main thread but called on the media thread.
+  mutable base::Lock new_key_cb_lock_;
+
   DISALLOW_COPY_AND_ASSIGN(AesDecryptor);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_CRYPTO_AES_DECRYPTOR_H_