This CL adds a new attribute that helps to identify
lower platform angle should use. We identified
several different use cases that ANGLE must
comply with when choose a display implementation.
Please refer to the
Support Matrix for EGL_ANGLE_platform_angle table

Bug: chromium:1084458
Change-Id: I6ea3d5081012ddf450f1c641343d1ba1a673483b
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2210151
Commit-Queue: Michael Spang <spang@chromium.org>
Reviewed-by: Michael Spang <spang@chromium.org>