tree bd9b2b3017bfc330e84a5fb50f1eb6966dd116de
parent 02cccfd9e790ba8758aba2b4f2a600a7d8fd1566
author Wei Jia <wjia@google.com> 1493400007 -0700
committer Wei Jia <wjia@google.com> 1493403143 -0700

IMediaExtractor: ensure users to check returned value by getTrack.

Test: fix the crash from the stream in the bug.
Bug: 37777357
Change-Id: Ia99907c396a2074a9419db9b8103a9325b290169