Fix incorrect opus seek preroll and flaky pre-skip removal.

media/filters/opus_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_FILTERS_OPUS_AUDIO_DECODER_H_
 #define MEDIA_FILTERS_OPUS_AUDIO_DECODER_H_
 
 #include "base/callback.h"
 #include "base/time/time.h"
 #include "media/base/audio_decoder.h"
@@ skipping 39 matching lines @@
   void ResetTimestampState();
   bool Decode(const scoped_refptr<DecoderBuffer>& input,
               scoped_refptr<AudioBuffer>* output_buffer);
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   AudioDecoderConfig config_;
   OutputCB output_cb_;
   OpusMSDecoder* opus_decoder_;
 
-  // When the input timestamp is |start_input_timestamp_| the decoder needs to
-  // drop |config_.codec_delay()| frames.
-  base::TimeDelta start_input_timestamp_;
+  // Hack to allow MSE to correctly support webm codec delay for opus; if an
+  // input buffer comes in with a timestamp less than this and no discard
+  // padding, the buffer will be marked for discard up to |start_timestamp_|.
+  base::TimeDelta start_timestamp_;
 
   scoped_ptr<AudioDiscardHelper> discard_helper_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(OpusAudioDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_OPUS_AUDIO_DECODER_H_