Support (E)AC3 passthrough

media/filters/android/media_codec_audio_decoder.h

Index: media/filters/android/media_codec_audio_decoder.h
diff --git a/media/filters/android/media_codec_audio_decoder.h b/media/filters/android/media_codec_audio_decoder.h
index 9e08d73807493c4e51e000d25ad47fa48e245b22..16c7bf09e8ee44e383a5eec8bdf1d2cef1ca0a44 100644
--- a/media/filters/android/media_codec_audio_decoder.h
+++ b/media/filters/android/media_codec_audio_decoder.h
@@ -165,9 +165,18 @@ class MEDIA_EXPORT MediaCodecAudioDecoder : public AudioDecoder,
   using InputQueue = std::deque<BufferCBPair>;
   InputQueue input_queue_;
 
+  // The queue for PTS and duration pair, which helps to bring duration
+  // information to decoded frames.
+  using PtsDurationPair = std::pair<base::TimeDelta, base::TimeDelta>;
+  using DurationQueue = std::deque<PtsDurationPair>;
+  DurationQueue duration_queue_;
+
   // Cached decoder config.
   AudioDecoderConfig config_;
 
+  // Indication to use passthrough decoder or not.
+  bool is_passthrough_;
+
   // Actual channel count that comes from decoder may be different than config.
   int channel_count_;
   ChannelLayout channel_layout_;