Revert "Post-process font-face rules in addRulesFromSheet."

This reverts http://src.chromium.org/viewvc/blink?view=revision&revision=161606.
It may have caused a 2% perf regression on some benchmarks.

BUG=317608
TBR=esprehn@chromium.org

Review URL: https://codereview.chromium.org/69283004

git-svn-id: svn://svn.chromium.org/blink/trunk@161741 bbb929c8-8fbe-4397-9dbb-9b2b20218538