Also adds tests for static png,jpg,gif
Was unable to simply expose drawDrawable because the JS
side of things does not understand inheritance (specifically,
it doesn't know what is a descendant from SkDrawable).
Change-Id: I6a833c93f22ef90ae12e901168ff428e20504209
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/242562
Reviewed-by: Kevin Lubick <kjlubick@google.com>
