The basic test we can use for perf testing internal classes with
mocks. The render tests are more specific to doing draw calls.

BUG=angleproject:956

Change-Id: Iade393facc30c8d7288b1b94a159ce3afe993021
Reviewed-on: https://chromium-review.googlesource.com/262775Reviewed-by: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>