The intent is to merge these two classes and remove redundant code.

Bug: b/172704839
Change-Id: I6eb66d7b4ddea3633b08df99464975cd59773b4e
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2524550
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com>
Reviewed-by: Tim Van Patten <timvp@google.com>