[graphite] Add ImageProviderTest

Bug: b/244602298
Change-Id: Ie88df98bad17015620b8c4ac9d654c9b4874d4c8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/577076
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
7 files changed