Revert "Change fontContainsCharacter to use SkTypeface::charsToGlyphs"

r160727 ended up causing a 14% performance regression on the html5 spec
test case on windows 7. As that change was intended to improve
performance by using a lighter weight API it clearly failed.

This change reverts r160727.

BUG=312945
R=tonyg@chromium.org

Review URL: https://codereview.chromium.org/52763002

git-svn-id: svn://svn.chromium.org/blink/trunk@160967 bbb929c8-8fbe-4397-9dbb-9b2b20218538