Rename enums in GrContextFactory to remove "GL"

Also, remove kNative as a separate context type and instead make it an alias for kGL or kGLES based on OS.

GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1845923004

Review URL: https://codereview.chromium.org/1845923004
21 files changed