Switch from using base64 BIOs to encoding funcs.

The OpenSSL base64 BIO is going away in BoringSSL. This change switches
to using the explicit base64 functions which are availible in both
OpenSSL and BoringSSL. The BoringSSL helper functions (i.e. for
calculating the size of the base64 encoding) are wrapped in #ifdefs so
that this change isn't coupled with the switch to BoringSSL. Once that
switch is complete, the #ifdefs can be removed.

Bug: 17409664
Change-Id: I42bac3bc93a1fb39feed39a8917d8e38d97629d3
Signed-off-by: Adam Langley <agl@google.com>
1 file changed