Vendor domains must not use Binder

On PRODUCT_FULL_TREBLE devices, non-vendor domains (except vendor
apps) are not permitted to use Binder. This commit thus:
* groups non-vendor domains using the new "coredomain" attribute,
* adds neverallow rules restricting Binder use to coredomain and
  appdomain only, and
* temporarily exempts the domains which are currently violating this
  rule from this restriction. These domains are grouped using the new
  "binder_in_vendor_violators" attribute. The attribute is needed
  because the types corresponding to violators are not exposed to the
  public policy where the neverallow rules are.

Test: mmm system/sepolicy
Test: Device boots, no new denials
Test: In Chrome, navigate to ip6.me, play a YouTube video
Test: YouTube: play a video
Test: Netflix: play a movie
Test: Google Camera: take a photo, take an HDR+ photo, record video with
      sound, record slow motion video with sound. Confirm videos play
      back fine and with sound.
Bug: 35870313
Change-Id: I0cd1a80b60bcbde358ce0f7a47b90f4435a45c95
diff --git a/private/mediametrics.te b/private/mediametrics.te
index 11f17d2..f8b2fa5 100644
--- a/private/mediametrics.te
+++ b/private/mediametrics.te
@@ -1,3 +1,3 @@
-# type_transition must be private policy the domain_trans rules could stay
-# public, but conceptually should go with this
+typeattribute mediametrics coredomain;
+
 init_daemon_domain(mediametrics)