Add support for midstream audio configuration changes.

media/filters/decoder_stream.h

 // Copyright 2014 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_FILTERS_DECODER_STREAM_H_
 #define MEDIA_FILTERS_DECODER_STREAM_H_
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
@@ skipping 80 matching lines @@
   // have been removed from AudioDecoder and plumbed elsewhere.
   Decoder* decoder() { return decoder_.get(); }
 
   // Allows callers to register for notification of splice buffers from the
   // demuxer.  I.e., DecoderBuffer::splice_timestamp() is not kNoTimestamp().
   typedef base::Callback<void(base::TimeDelta)> SpliceObserverCB;
   void set_splice_observer(const SpliceObserverCB& splice_observer) {
     splice_observer_cb_ = splice_observer;
   }
 
+  // Allows callers to register for notification of config changes; this is
+  // called immediately after recieving the 'kConfigChanged' status from the
+  // DemuxerStream, before any action is taken to handle the config change.
+  typedef base::Closure ConfigChangeObserverCB;
+  void set_config_change_observer(
+      const ConfigChangeObserverCB& config_change_observer) {
+    config_change_observer_cb_ = config_change_observer;
+  }
+
  private:
   enum State {
     STATE_UNINITIALIZED,
     STATE_INITIALIZING,
     STATE_NORMAL,  // Includes idle, pending decoder decode/reset/stop.
     STATE_FLUSHING_DECODER,
     STATE_PENDING_DEMUXER_READ,
     STATE_REINITIALIZING_DECODER,
     STATE_STOPPED,
     STATE_ERROR
@@ skipping 56 matching lines @@
 
   DemuxerStream* stream_;
 
   scoped_ptr<DecoderSelector<StreamType> > decoder_selector_;
 
   // These two will be set by DecoderSelector::SelectDecoder().
   scoped_ptr<Decoder> decoder_;
   scoped_ptr<DecryptingDemuxerStream> decrypting_demuxer_stream_;
 
   SpliceObserverCB splice_observer_cb_;
+  ConfigChangeObserverCB config_change_observer_cb_;
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<DecoderStream<StreamType> > weak_factory_;
 
   // This is required so the VideoFrameStream can access private members in
   // FinishInitialization() and ReportStatistics().
   DISALLOW_IMPLICIT_CONSTRUCTORS(DecoderStream);
 };
 
 template <>
 bool DecoderStream<DemuxerStream::AUDIO>::CanReadWithoutStalling() const;
 
 typedef DecoderStream<DemuxerStream::VIDEO> VideoFrameStream;
 typedef DecoderStream<DemuxerStream::AUDIO> AudioBufferStream;
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_DECODER_STREAM_H_