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: I6041e7e49ca5cc65f90fc8ae6f1b084e4639d769
Reviewed-on: https://chromium-review.googlesource.com/c/1330315
Commit-Queue: Tim Van Patten <timvp@google.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>