DO NOT MERGE - SoftVPX: fix nFilledLen overflow am: b7ba49c1a0  -s ours am: c7dd19198c am: 3cb33198d6 am: baba64dd05  -s ours am: aad3552a45 am: bdb5802757
am: c657f26400

Change-Id: If2c00fe5364a1f848d4b7bd3b708c9c56487b1cd