Request specific ANGLE context versions.

Using the ANGLE_create_context_backwards_compatible extension, request
explicit ANGLE context versions to make sure test coverage of context
versions matches Chrome.

BUG=skia:10309

Change-Id: Ifa4a36851a0517b369d094e5707348a20eaf3879
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/293339
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
Auto-Submit: Geoff Lang <geofflang@google.com>
1 file changed