Reject unicode-range: inherit in @font-face

The 'inherit' and 'initial' values are not allowed in @font-face
descriptors, but CSS parser accepts them. We should reject them.
This was a regression from Blink r157875 that caused assertion failure.

BUG=293707
TEST=fast/css/font-face-inherit-initial.html

Review URL: https://chromiumcodereview.appspot.com/23890035

git-svn-id: svn://svn.chromium.org/blink/trunk@157937 bbb929c8-8fbe-4397-9dbb-9b2b20218538