* commit '9f94208953fc8da72140c2964bcf12ff5b485784': cherrypick from master docs: GCM changes Change-Id: Id5454e70455bae14ab4605021a6c1bcab0292ae9 Doc update: Misc minor GCM updates.
* commit '9f94208953fc8da72140c2964bcf12ff5b485784': cherrypick from master docs: GCM changes Change-Id: Id5454e70455bae14ab4605021a6c1bcab0292ae9 Doc update: Misc minor GCM updates.