Another signedness error. Leave a TODO to possibly resolve EVP_DecodeBlock's
ignoring padding. Document some of the Init/Update/Finish versions' behavior.
Change-Id: I78a72c3163f8543172a7008b2d09fb10e003d957
Reviewed-on: https://boringssl-review.googlesource.com/1230
Reviewed-by: Adam Langley <agl@google.com>
Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta).
(This change contains substantial changes from the original and
effectively starts a new history.)