Update PluginInstance for audio support for content decryption.

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 113 matching lines @@
   // upon completion.
   // |key_added_cb| should be called when a key is added to the decryptor.
   virtual void InitializeAudioDecoder(scoped_ptr<AudioDecoderConfig> config,
                                       const DecoderInitCB& init_cb,
                                       const KeyAddedCB& key_added_cb) = 0;
   virtual void InitializeVideoDecoder(scoped_ptr<VideoDecoderConfig> config,
                                       const DecoderInitCB& init_cb,
                                       const KeyAddedCB& key_added_cb) = 0;
 
   // Helper structure for managing multiple decoded audio buffers per input.
+  // TODO(xhwang): Rename this to AudioFrames.
   typedef std::list<scoped_refptr<Buffer> > AudioBuffers;
 
   // Indicates completion of audio/video decrypt-and-decode operation.
   //
   // First parameter: The status of the decrypt-and-decode operation.
   // - Set to kSuccess if the encrypted buffer is successfully decrypted and
   //   decoded. In this case, the decoded frame/buffers can be/contain:
   //   1) NULL, which means the operation has been aborted.
   //   2) End-of-stream (EOS) frame, which means that the decoder has hit EOS,
   //      flushed all internal buffers and cannot produce more video frames.
@@ skipping 41 matching lines @@
   // The decoder can be reinitialized after it is uninitialized.
   virtual void DeinitializeDecoder(StreamType stream_type) = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Decryptor);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_DECRYPTOR_H_