change computeByteSize to return max_size_t on overflow

Bug: skia:7132
Change-Id: I41045640ee62b2c988a84370ead5034bbccc6daf
Reviewed-on: https://skia-review.googlesource.com/56620
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Mike Reed <reed@google.com>
9 files changed