DO NOT MERGE - MPEG4Extractor: Check mLastTrack before dereferencing. am: 25d34cacde am: 428493c16d  -s ours am: c2af35e25d am: 4da47f34d9 am: 72d1936749
am: 203ce3a3e5  -s ours

Change-Id: I23ec9f604cc85cc8e470805db6e43e91e13df19a