[automerger] Check NAL size before looking inside am: e0c020969d am: 8c4ae8057c am: 767a82a9d6 am: f7d9bba9b1 am: e04b7c8c06 am: 25e199f787 am: 93962ef505 am: 714148f6eb am: b6fdd7ee95 am: 3631c04dfa am: 68adda01b0 am: 68e58ff3bd am: 078f1de778
am: a1f05a7197

Change-Id: Ieefec18019f6c43214a108b0a86adc4962163a77