DO NOT MERGE MPEG4Extractor: ensure kKeyTrackID exists before creating an MPEG4Source as track. am: b016207fc2 am: e2ca751723 am: 3d1df4f411  -s ours
am: 1ed4ec584b  -s ours

* commit '1ed4ec584b736febb95e5fe390bfc1ffea039b99':
  DO NOT MERGE MPEG4Extractor: ensure kKeyTrackID exists before creating an MPEG4Source as track.

Change-Id: Ia777e26e03f925fff45db6a4556c05758923a94c