Use cc::Scheduler to drive the surfaces server

The CL uses the cc::Scheduler to drive the surfaces server instead of an ad-hoc
timer. Currently we're only using a tiny piece of the scheduler's functionality,
but we think we'll use more over time.

In this CL, I've created SurfacesScheduler as a facade over cc::Scheduler so that
we can understand which parts of cc::Scheduler we're actually using.

This is a copy of https://codereview.chromium.org/756693004/ merged to
tip of tree after the services directory move.

TBR=jamesr@chromium.org

Review URL: https://codereview.chromium.org/775423002