This fixes a bug where AppRTCMobile would crash at runtime when
built without VP9 support.
Bug: webrtc:8602
Change-Id: Id2db79c3ff8136f06dc049afcc5197e9356fd25b
Reviewed-on: https://webrtc-review.googlesource.com/27983
Reviewed-by: Oleh Prypin <oprypin@webrtc.org>
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Commit-Queue: Oleh Prypin <oprypin@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20982}