This adds several utilities as replacements for new and delete and makes
bssl::UniquePtr work with our private types.
Later work can convert more incrementally. I did this one more
aggressively to see how it'd work. Unfortunately, in doing so, I needed
to remove the NULL SSL_AEAD_CTX "method" receiver trick to appease
clang. The null cipher is now represented by a concrete SSL_AEAD_CTX.
The long-lived references to SSL_AEAD_CTX are not yet in types with
constructors, so they still bare Delete rather than UniquePtr for now.
Though this does mean we may be able to move the sequence number into
SSLAEADContext later which is one less object for DTLS to carry around.
Bug: 132
Change-Id: I506b404addafb692055d5709b0ca6d5439a4e6be
Reviewed-on: https://boringssl-review.googlesource.com/18164
Reviewed-by: Adam Langley <agl@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
cfc11c2320