Merge FontPlatformData::setupPaint and setupPaintForFont on Win

We currently have two different setupPaint methods for the font
graphics code on windows, one used for drawing (setupPaintForFont)
and one used for metrics for the non-gdi code path (setupPaint).

This is silly and error prone, merge the two into
FontPlatformData::setupPaint.

BUG=249099

Review URL: https://chromiumcodereview.appspot.com/24422003

git-svn-id: svn://svn.chromium.org/blink/trunk@158352 bbb929c8-8fbe-4397-9dbb-9b2b20218538