media: Support better decoder switching

media/base/audio_decoder.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_AUDIO_DECODER_H_
 #define MEDIA_BASE_AUDIO_DECODER_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 25 matching lines @@
   typedef base::Callback<void(DecodeStatus)> DecodeCB;
 
   AudioDecoder();
 
   // Fires any pending callbacks, stops and destroys the decoder.
   // Note: Since this is a destructor, |this| will be destroyed after this call.
   // Make sure the callbacks fired from this call doesn't post any task that
   // depends on |this|.
   virtual ~AudioDecoder();
 
-  // Returns the name of the decoder for logging purpose.
+  // Returns the name of the decoder for logging and decoder selection purposes.
+  // This name should be available immediately after construction (e.g. before
+  // Initialize() is called). It should also be stable in the sense that the
+  // name does not change across multiple constructions.
+  // TODO(xhwang): Rename this method since the name is not only for display.
   virtual std::string GetDisplayName() const = 0;
 
   // Initializes an AudioDecoder with |config|, executing the |init_cb| upon
   // completion.
   //
   // |cdm_context| can be used to handle encrypted buffers. May be null if the
   // stream is not encrypted.
   // |init_cb| is used to return initialization status.
   // |output_cb| is called for decoded audio buffers (see Decode()).
   virtual void Initialize(const AudioDecoderConfig& config,
@@ skipping 22 matching lines @@
   // Returns true if the decoder needs bitstream conversion before decoding.
   virtual bool NeedsBitstreamConversion() const;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AudioDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_AUDIO_DECODER_H_