Remove non-harfbuzz code in SkiaFontWin and FontPlatformDataWin

Remove the remaining hfont and uniscribe support code in the windows
specific SkiaFontWin and FontPlatformDataWin classes.

R=leviw@chromium.org

Review URL: https://codereview.chromium.org/195813013

git-svn-id: svn://svn.chromium.org/blink/trunk@169282 bbb929c8-8fbe-4397-9dbb-9b2b20218538