sync compositor: pass simple gfx types by const ref

See bug for reasoning

BUG=159273

Review URL: https://codereview.chromium.org/1417893006

Cr-Commit-Position: refs/heads/master@{#356653}
void SynchronousCompositorOutputSurface::DetachFromClient() {
  DCHECK(CalledOnValidThread());
  if (registered_) {
    registry_->UnregisterOutputSurface(routing_id_, this);
  }
  cc::OutputSurface::DetachFromClient();
}

void SynchronousCompositorOutputSurface::DetachFromClient() {
  DCHECK(CalledOnValidThread());
  if (registered_) {
    registry_->UnregisterOutputSurface(routing_id_, this);
  }
  cc::OutputSurface::DetachFromClient();
}
