Will be used for mid-execution capture. Only has a
stubbed-out implementation right now.

Bug: angleproject:3944
Change-Id: I6ddae07907ecbdbd3be9a5d2d3fcafeb425445e4
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1878888
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Cody Northrop <cnorthrop@google.com>