Some hardening of isolated processes by restricting access to services.

Services now must explicitly opt in to being accessed by isolated
processes.  Currently only the activity manager and surface flinger
allow this.  Activity manager is needed so that we can actually
bring up the process; SurfaceFlinger is needed to be able to get the
display information for creating the Configuration.  The SurfaceFlinger
should be safe because the app doesn't have access to the window
manager so can't actually get a surface to do anything with.

The activity manager now protects most of its entry points against
isolated processes.

Change-Id: I0dad8cb2c873575c4c7659c3c2a7eda8e98f46b0