DO NOT MERGE MPEG4Extractor: ensure kKeyTrackID exists before creating an MPEG4Source as track.
am: b016207fc2

* commit 'b016207fc2442420e8d3a8633575ffe4fc29fef3':
  DO NOT MERGE MPEG4Extractor: ensure kKeyTrackID exists before creating an MPEG4Source as track.

Change-Id: I81cdae1a917cfcd712e800cf3edfd168b1c89c32