Implement support for using GL ES 3.0 with command buffer

Adds a new 'api': --config gpu(api=commandbuffer3) for dm/nanobench.

BUG=skia:4943
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1684413003

Review URL: https://codereview.chromium.org/1684413003
17 files changed