This change also prevents hardware acceleration when the ViewRoot is in the
system process. This causes problem in EGL intialization because of having
both a SurfaceControl and a Surface. This is not needed and better to leave
it off anyway (so that preview windows don't get unnecessary hw acceleration.)
Change-Id: I1cc55d7fb9a4c1a9c4c59f11f49d3e44de78acef