Reland r169206 "Enable Woff 2.0 font compression format by default"

This feature was once enabled in M35 but we had to unlaunch it (wire
format changes being under consideration). The decoder patch for the
format change is landed [1], and we are not expecting further format
change at the moment.

[1] https://code.google.com/p/ots/source/detail?r=113

> Enable Woff 2.0 font compression format by default
>
> Feature Dashboard: http://www.chromestatus.com/features/6718644721549312
> PSA: https://groups.google.com/a/chromium.org/d/topic/chromium-dev/j27Ou4RtvQI/discussion
>
> BUG=242809, 223731
>
> Review URL: https://codereview.chromium.org/199773002

Review URL: https://codereview.chromium.org/265833004

git-svn-id: svn://svn.chromium.org/blink/trunk@173589 bbb929c8-8fbe-4397-9dbb-9b2b20218538