Instead of referring to command graphs we can refer to if the resource
is in use by "ANGLE" or the "Driver". This will make the methods more
consistent when we switch away from the command graph.

Bug: angleproject:4029
Change-Id: I3045a4eb2a38234ef331c0662694656065590ae1
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2003234
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>