Test CTFonts for equality, not just name and style.

The current code looks up CTFonts from descriptors by just name and style.
This is not sufficient, for example Avenir Book and Avenir Roman have the
same family name but the same basic style, but are obviously not the same.

BUG=skia:5162
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1860993004

Review URL: https://codereview.chromium.org/1860993004
1 file changed