[automerger] Add some error/overflow checks in codebook handling am: 6eb63e1192 am: bc4bde3bee am: 632704bab3 am: 9cea7b942e am: 57035e3928 am: 6d0e814689
am: 14cbdba347

Change-Id: Id4794c47d930d4aa61907983e3f38a84ed579648