Fix mp4 keyframe parsing, removing unused stss parsing.

media/formats/mp4/mp4_stream_parser.cc

Index: media/formats/mp4/mp4_stream_parser.cc
diff --git a/media/formats/mp4/mp4_stream_parser.cc b/media/formats/mp4/mp4_stream_parser.cc
index 8f4a2284346298afa54f4137aa40955df3dcbc8c..3cad03d4649f894a4cfd54f36b742618c6e45553 100644
--- a/media/formats/mp4/mp4_stream_parser.cc
+++ b/media/formats/mp4/mp4_stream_parser.cc
@@ -516,12 +516,9 @@ bool MP4StreamParser::EnqueueSample(BufferQueue* audio_buffers,
   // TODO(wolenetz/acolwell): Validate and use a common cross-parser TrackId
   // type and allow multiple tracks for same media type, if applicable. See
   // https://crbug.com/341581.
-  //
-  // NOTE: MPEG's "random access point" concept is equivalent to the
-  // downstream code's "is keyframe" concept.
   scoped_refptr<StreamParserBuffer> stream_buf =
       StreamParserBuffer::CopyFrom(&frame_buf[0], frame_buf.size(),
-                                   runs_->is_random_access_point(),
+                                   runs_->is_keyframe(),
                                    buffer_type, 0);
 
   if (decrypt_config)
@@ -533,7 +530,6 @@ bool MP4StreamParser::EnqueueSample(BufferQueue* audio_buffers,
 
   DVLOG(3) << "Pushing frame: aud=" << audio
            << ", key=" << runs_->is_keyframe()
-           << ", rap=" << runs_->is_random_access_point()
            << ", dur=" << runs_->duration().InMilliseconds()
            << ", dts=" << runs_->dts().InMilliseconds()
            << ", cts=" << runs_->cts().InMilliseconds()