This will allow us to use the same method with EGL without
complications.

Bug: angleproject:2621
Change-Id: I03dea2291adc13025723fe02eb47b76a74cef911
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2562679
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Cody Northrop <cnorthrop@google.com>