This adds two subclasses: RecordableGraphResource and
QueryGraphResource. Each specializes for Buffer/Image/Frambuffer use
cases and Query use cases respectively. No virtual functions are added
to keep best performance.

We also change the CommandGraph API slightly to optimize away the check
for a barrier resource. This requires exposing the set current barrier
API on the CommandGraph.

Bug: angleproject:2828
Change-Id: I1c23f52bfe04cc682a00b245d63c3ac9a651615d
Reviewed-on: https://chromium-review.googlesource.com/c/1305994
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>