vr_wm functionality is moved in VrCore, so remove this service.

Bug: 37542947, 36506799
Test: Ran on device and verified there are no permission errors while in
VR
Change-Id: I37fd34e96babec2a990600907f61da8c358ecc89

Allow the services to do binder calls to system_server in order to check
for app permissions.

Bug: 37542947
Test: Compiled and ran on device ensuring no permission errors
Change-Id: If91895607eb118f689cf2e11c63945e9f83bf2a0

Bug: 37542947
Test: Compiled and ran on device to ensure no access errors while in VR
Change-Id: Ia685676d82f1f10f2bd371a13879d00fe63a9ea6

VR HWC is being split out of VR Window Manager. It creates a HW binder
interface used by SurfaceFlinger which implements the HWComposer HAL and
a regular binder interface which will be used by a system app to receive
the SurfaceFlinger output.

Bug: b/36051907
Test: Ran in permissive mode and ensured no permission errors show in
logcat.

Change-Id: If1360bc8fa339a80100124c4e89e69c64b29d2ae