Change fontContainsCharacter to use SkTypeface::charsToGlyphs

Change FontCacheSkiaWin::fontContainsCharacter to use the SkTypeface
charsToGlyphs API instead of the SkPaint textToGlyphs version.

The SkTypeface one is faster and is what we use in GlyphPageTreeNode
as of r160612.

R=reed@chromium.org
BUG=

Review URL: https://codereview.chromium.org/46333002

git-svn-id: svn://svn.chromium.org/blink/trunk@160727 bbb929c8-8fbe-4397-9dbb-9b2b20218538