Attempt decoder fallback if first decode fails

media/filters/decoder_stream.h

Index: media/filters/decoder_stream.h
diff --git a/media/filters/decoder_stream.h b/media/filters/decoder_stream.h
index a7f084fa3f6f806caff60e210708abe6a86ec85a..83e41f22f580e5445b8617157d493899ae19540c 100644
--- a/media/filters/decoder_stream.h
+++ b/media/filters/decoder_stream.h
@@ -122,6 +122,14 @@ class MEDIA_EXPORT DecoderStream {
     return previous_decoder_.get();
   }
 
+  int get_pending_buffers_size_for_testing() const {
+    return pending_buffers_.size();
+  }
+
+  int get_fallback_buffers_size_for_testing() const {
+    return fallback_buffers_.size();
+  }
+
  private:
   enum State {
     STATE_UNINITIALIZED,
@@ -131,7 +139,10 @@ class MEDIA_EXPORT DecoderStream {
     STATE_PENDING_DEMUXER_READ,
     STATE_REINITIALIZING_DECODER,
     STATE_END_OF_STREAM,  // End of stream reached; returns EOS on all reads.
-    STATE_ERROR
+    STATE_ERROR,
+    // TODO(tguilbert): support config changes during decoder fallback, see
+    // crbug.com/603713
+    STATE_CONFIG_CHANGE_RECEIVED_WHILE_REINITIALIZING_DECODER
   };
 
   void SelectDecoder(CdmContext* cdm_context);
@@ -225,8 +236,18 @@ class MEDIA_EXPORT DecoderStream {
   // Tracks the duration of incoming packets over time.
   MovingAverage duration_tracker_;
 
+  // Stores buffers that might be reused if the decoder fails right after
+  // Initialize().
+  std::deque<scoped_refptr<DecoderBuffer>> pending_buffers_;
+
+  // Stores buffers that are garanteed to be fed to the decoder before fetching
+  // more from the demuxer stream. Populated by |pending_buffers_| on decoder
+  // fallback.
+  std::deque<scoped_refptr<DecoderBuffer>> fallback_buffers_;
+
   // NOTE: Weak pointers must be invalidated before all other member variables.
-  base::WeakPtrFactory<DecoderStream<StreamType> > weak_factory_;
+  base::WeakPtrFactory<DecoderStream<StreamType>> weak_factory_;
+  base::WeakPtrFactory<DecoderStream<StreamType>> decode_weak_factory_;

[sandersd (OOO until July 31), 2016/04/14 23:10:30]

This should have a comment, since the usage pattern isn't common in media yet.
Just explain that it will be invalidated each time we fall back to a new
decoder, so that outstanding callbacks will be dropped.

 };
 
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