This should also trim down code size since WebGL should never want
GrGLMakeAssembledGLInterface only GrGLMakeAssembledGLESInterface
Bug: skia:
Change-Id: I9246d467847eeb91517c56075077b3e26c4ee336
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/201223
Reviewed-by: Nathaniel Nifong <nifong@google.com>