Add comparison of rendered SkPictures to Serialization unit test

This identifies a possible bug with font serialization (changing the
typeface on line 444 causes the test to fail).

Change-Id: I4e2c9d21cd03586e043b8d82eeff6607bb02b380
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/226510
Auto-Submit: Ben Wagner aka dogben <benjaminwagner@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Ben Wagner aka dogben <benjaminwagner@google.com>
1 file changed