Use font manager for fallback on Android.

The corresponding Chromium side change is https://codereview.chromium.org/450733002/ . These two can be committed in any order.

Review URL: https://codereview.chromium.org/447233003

git-svn-id: svn://svn.chromium.org/blink/trunk@179753 bbb929c8-8fbe-4397-9dbb-9b2b20218538