Fix NALU extraction of unit starts with a 0x00 nalType
Fix NALU extraction of unit starts with a 0x00 nalType

by not backing up beyond the start of the nal unit.

Change-Id: I5fba9913202de416e634e5f39181be62b72b2469
related-to-bug: 4770290

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base