[webcrypto] Reject AES-GCM tag lengths other than 32, 64, 96, 104, 112, 120, 128 bits.

This matches the spec update https://dvcs.w3.org/hg/webcrypto-api/rev/1ed0fb7da636.

(Before it was possible to use a tag length of 0 and have it succeed)

BUG=245025

Review URL: https://codereview.chromium.org/165373008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252769 0039d316-1c4b-4281-b951-d872f2087c98
6 files changed