Change HMAC::Sign() to take base::StringPiece instead of string.

Do this to avoid memory copying when signning data in char*.
base::StringPiece nicely handles both cases.

BUG=None
TEST=crypto_unittests

Review URL: http://codereview.chromium.org/7033035

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@88049 0039d316-1c4b-4281-b951-d872f2087c98
5 files changed