Add libFuzzer style fuzzer for NullGLCanvas for use on OSS-Fuzz.

Bug: 827225
Change-Id: Icb30c0c234326340213af0cc402a4124dd0336b3
Reviewed-on: https://skia-review.googlesource.com/117150
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>
1 file changed