Update ANGLE Developer Options

Update ANGLE developer options to allow selecting the OpenGL driver
(default, ANGLE, native) for each app as well as forcing ANGLE for all
apps.

Bug: angleproject:2962
Test: Verify the default/ANGLE/native values are saved and applied and
used by the loader.

Change-Id: I6737b11bc061318cf8438c8161593ca70239590f
Reviewed-on: https://chromium-review.googlesource.com/c/1354101Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Tim Van Patten <timvp@google.com>