Revert SurfaceView background implementation.

We changed the SurfaceView background to be a boundless
child layer. However this was a semantic change. Each SurfaceView now
has its own background behind it instead of the backgrounds being
behind all SurfaceView. This causes an issue with some apps which
have an invisible SurfaceView hanging out for no particular reason.

Revert "SurfaceView: Correct comparison operator.",
"SurfaceView: Only show background when behind ViewRoot.",
"SurfaceView: Check correct OPAQUE flag for background visibility.",
"Correct SurfaceView background visibility.",
"Replace SurfaceView background with boundless color layer."

Bug: 123920952
Test: SurfaceViewTest. SurfaceViewSurfaceValidatorTest
Change-Id: I88ff31542ee0139d15c84ed2d6791c5cd455604b