Porting of HKDF changes from server.

Merge internal CL: 40300624


Review URL: https://chromiumcodereview.appspot.com/12326029

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@184133 0039d316-1c4b-4281-b951-d872f2087c98
4 files changed