Prevent read of uninitialized memory Bug: 173720767 Test: atest MediaPlayerTest Change-Id: Ib6a3d24e07915e8af9d019e54d0501b74aa4671d (cherry picked from commit 42a97f5648e9345461422310039fc9d1def0a91a) (cherry picked from commit e4497aaaabb2ceadec970882c82ee199b7ac6592)