This can allow us to get some profiling measurements on ANGLE vs a
native driver. We correlate host times with GL times using the blocking
timestamp query. We also time RenderPasses/FBO switches using the
trace instrumentation we added in an earlier patch combined with timer
queries.

Not currently instrumented for the current tests. We'll need to re-run
capture to get the callbacks working correctly.

Bug: angleproject:4433
Change-Id: I8f61774a3a090ac9460a378d34715a72954d1331
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2080597Reviewed-by: Cody Northrop <cnorthrop@google.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>