Remove dead code from FontHarfBuzz.

This code looks like it is left over from before the conversion to HarfBuzz-ng.
The SkPaints that are created are not being used anywhere.

BUG=

Review URL: https://chromiumcodereview.appspot.com/23684062

git-svn-id: svn://svn.chromium.org/blink/trunk@157699 bbb929c8-8fbe-4397-9dbb-9b2b20218538