Encrypted Media: Support Audio Decrypt-Only.

media/base/decryptor.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 MEDIA_BASE_DECRYPTOR_H_
 #define MEDIA_BASE_DECRYPTOR_H_
 
 #include <list>
 #include <string>
 
@@ skipping 186 matching lines @@
   // This method can be called any time after Initialize{Audio|Video}Decoder()
   // has been called (with the correct stream type).
   // After this operation, the decoder is set to an uninitialized state.
   // The decoder can be reinitialized after it is uninitialized.
   virtual void DeinitializeDecoder(StreamType stream_type) = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Decryptor);
 };
 
+// Callback to notify decryptor creation.
+typedef base::Callback<void(Decryptor*)> DecryptorNotificationCB;
+// Callback to request/cancel decryptor creation notification.
+// Calling this callback with a non-null callback registers decryptor creation
+// notification. When the decryptor is created, notification will be sent
+// through the provided callback.
+// Calling this callback with a null callback cancels previously registered
+// decryptor creation notification. Any previously provided callback will be
+// fired immediately with NULL.
+typedef base::Callback<void(const DecryptorNotificationCB&)>
+    RequestDecryptorNotificationCB;
+
 }  // namespace media
 
 #endif  // MEDIA_BASE_DECRYPTOR_H_