Update Decryptor interface to support audio decoding.

media/base/decryptor.h

Index: media/base/decryptor.h
diff --git a/media/base/decryptor.h b/media/base/decryptor.h
index b422dc586a696dde763aaa019dd7216ae17613e9..f898c9255978257cb3b686e167cee5f072f9382b 100644
--- a/media/base/decryptor.h
+++ b/media/base/decryptor.h
@@ -5,15 +5,19 @@
 #ifndef MEDIA_BASE_DECRYPTOR_H_
 #define MEDIA_BASE_DECRYPTOR_H_
 
+#include <list>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
+#include "media/base/audio_decoder.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
+class AudioDecoderConfig;
+class Buffer;
 class DecoderBuffer;
 class VideoDecoderConfig;
 class VideoFrame;
@@ -46,6 +50,11 @@ class MEDIA_EXPORT Decryptor {
     kError  // Key is available but an error occurred during decryption.
   };
 
+  enum StreamType {
+    kAudio,
+    kVideo
+  };
+
   Decryptor();
   virtual ~Decryptor();
 
@@ -89,17 +98,20 @@ class MEDIA_EXPORT Decryptor {
   // Decrypts the |encrypted| buffer. The decrypt status and decrypted buffer
   // are returned via the provided callback |decrypt_cb|. The |encrypted| buffer
   // must not be NULL.
-  // Decrypt() should not be called until any previous DecryptCB has completed.
-  // Thus, only one DecryptCB may be pending at a time.
-  virtual void Decrypt(const scoped_refptr<DecoderBuffer>& encrypted,
+  // Decrypt() should not be called until any previous DecryptCB of the same
+  // |stream_type| has completed. Thus, only one DecryptCB may be pending at
+  // a time for a given |stream_type|.
+  virtual void Decrypt(StreamType stream_type,
+                       const scoped_refptr<DecoderBuffer>& encrypted,
                        const DecryptCB& decrypt_cb) = 0;
 
-  // Cancels the scheduled decryption operation and fires the pending DecryptCB
-  // immediately with kSuccess and NULL.
-  // Decrypt() should not be called again before the pending DecryptCB is fired.
-  virtual void CancelDecrypt() = 0;
+  // Cancels the scheduled decryption operation for |stream_type| and fires the
+  // pending DecryptCB immediately with kSuccess and NULL.
+  // Decrypt() should not be called again before the pending DecryptCB for the
+  // same |stream_type| is fired.
+  virtual void CancelDecrypt(StreamType stream_type) = 0;
 
-  // Indicates completion of decoder initialization.
+  // Indicates completion of audio/video decoder initialization.
   //
   // First Parameter: Indicates initialization success.
   // - Set to true if initialization was successful. False if an error occurred.
@@ -108,50 +120,69 @@ class MEDIA_EXPORT Decryptor {
   // Indicates that a key has been added to the Decryptor.
   typedef base::Callback<void()> KeyAddedCB;
 
-  // Initializes a video decoder with the given |config|, executing the
-  // |init_cb| upon completion.
-  // Note: DecryptAndDecodeVideo(), ResetVideoDecoder() and StopVideoDecoder()
-  // can only be called after InitializeVideoDecoder() succeeded.
+  // Initializes a decoder with the given |config|, executing the |init_cb|
+  // 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;
 
-  // Indicates completion of video decrypting and decoding operation.
+  // Helper structure for managing multiple decoded audio buffers per input.
+  typedef std::list<scoped_refptr<Buffer> > AudioBuffers;

[xhwang, 2012/10/17 00:18:59]

One status per decode call should be sufficient. Drop extra status to simplify
implementation.

+
+  // Indicates completion of audio/video decrypt-and-decode operation.
   //
-  // First parameter: The status of the decrypting and decoding 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 video frame can be:
+  //   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.
-  //   3) Decrypted and decoded video frame.
+  //   3) Decrypted and decoded video frame or audio buffer.
   // - Set to kNoKey if no decryption key is available to decrypt the encrypted
-  //   buffer. In this case the decoded video frame must be NULL.
+  //   buffer. In this case the second parameter must be NULL.

[ddorwin, 2012/10/17 02:52:33]

s/second/buffer/ (or data or something)
I realize the name is not consistent, but position could easily get out of data
upon refactoring.
Same two times below.

[xhwang, 2012/10/17 22:29:06]

Done.

   // - Set to kNeedMoreData if more data is needed to produce a video frame. In
-  //   this case the decoded video frame must be NULL.
+  //   this case the second parameter must be NULL.
   // - Set to kError if unexpected error has occurred. In this case the
-  //   decoded video frame must be NULL.
-  // Second parameter: The decoded video frame.
+  //   second parameter must be NULL.
+  // Second parameter: The decoded video frame or audio buffers.
+  typedef base::Callback<void(Status,
+                              const scoped_ptr<AudioBuffers>&)> AudioDecodeCB;
   typedef base::Callback<void(Status,
                               const scoped_refptr<VideoFrame>&)> VideoDecodeCB;
 
   // Decrypts and decodes the |encrypted| buffer. The status and the decrypted
-  // buffer are returned via the provided callback |video_decode_cb|.
+  // buffer are returned via the provided callback.
   // The |encrypted| buffer must not be NULL.
   // At end-of-stream, this method should be called repeatedly with
-  // end-of-stream DecoderBuffer until no video frame can be produced.
+  // end-of-stream DecoderBuffer until no frame/buffer can be produced.
+  // These two methods can only be called after the corresponding decoder has

[ddorwin, 2012/10/17 02:52:33]

s/two//

[xhwang, 2012/10/17 22:29:06]

Done.

+  // been successfully initialized.
+  virtual void DecryptAndDecodeAudio(
+      const scoped_refptr<DecoderBuffer>& encrypted,
+      const AudioDecodeCB& audio_decode_cb) = 0;
   virtual void DecryptAndDecodeVideo(
       const scoped_refptr<DecoderBuffer>& encrypted,
       const VideoDecodeCB& video_decode_cb) = 0;
 
-  // Cancels scheduled video decrypt-and-decode operations and fires any pending
-  // VideoDecodeCB immediately with kError and NULL frame.
-  virtual void CancelDecryptAndDecodeVideo() = 0;
-
-  // Stops decoder and sets it to an uninitialized state.
-  // The decoder can be reinitialized by calling InitializeVideoDecoder() after
-  // it is stopped.
-  virtual void StopVideoDecoder() = 0;
+  // Resets the decoder to an initialized clean state, cancels any scheduled
+  // decrypt-and-decode operations and fires any pending

[ddorwin, 2012/10/17 02:52:33]

A comma before a >2 item "and" would probably be helpful here and the next
paragraph since they are so long and detailed.

[xhwang, 2012/10/17 22:29:06]

Done.

+  // AudioDecodeCB/VideoDecodeCB immediately with kError and NULL.
+  // This method can only be called after the corresponding decoder has been
+  // successfully initialized.
+  virtual void ResetDecoder(StreamType stream_type) = 0;
+
+  // Uninitializes the decoder and sets it to an uninitialized state, cancels

[ddorwin, 2012/10/17 02:52:33]

// Frees decoder resources and...?

[ddorwin, 2012/10/17 07:16:05]

s/Frees/Releases/

[xhwang, 2012/10/17 22:29:06]

Done.

[xhwang, 2012/10/17 22:29:06]

Done.

+  // any scheduled initialization or decrypt-and-decode operations and fires
+  // any pending DecoderInitCB/AudioDecodeCB/VideoDecodeCB immediately with
+  // false or kError/NULL respectively.

[ddorwin, 2012/10/17 02:52:33]

It's not clear how these map respectively since the numbers mismatch.

[xhwang, 2012/10/17 22:29:06]

Done.

+  // This method can be called any time after Initialize{Audio|Video}Decoder()
+  // has been called (with the correct stream type).
+  // The decoder can be reinitialized after it is uninitialized.
+  virtual void DeinitializeDecoder(StreamType stream_type) = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Decryptor);