[automerger] stagefright: avoid buffer overflow in base64 decoder am:...

[automerger] stagefright: avoid buffer overflow in base64 decoder am: 5e96386a am: 5045de6f am: 8f6c537f am: 4d76a4b5 am: 5e5bb2a8 am: 61c116ad am: 9064a5c7 am: 25b927e2 am: 0ad7b10c am: 8fbbb6af

Change-Id: I257c00c2aa626ff061150e3a407b7b41abf8e03a