[webcrypto] Some fixes for HMAC
* Wire up HMAC SHA224, HMAC SHA384, HMAC SHA512 for NSS.
* When generating an HMAC key and the key length was not specified use
the underlying block size for the key length (as this is the maximum
length of the key). The OpenSSL version had a bug where it would not
select the block size.
* Fix a test which intended to check randomness.
BUG=245025
Review URL: https://codereview.chromium.org/108653015
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242149 0039d316-1c4b-4281-b951-d872f2087c98
5 files changed