Visit Uris in RemoteViews for granting purposes.

RemoteViews end up passing around Uris, so we need to extend Uri
permission grants for them to ensure the recipient of a Notification
object is able to render its contents.

Bug: 9069730
Test: atest frameworks/base/services/tests/uiservicestests/src/com/android/server/notification
Change-Id: Id31b5adaf2ee66113a1b503e32126aeddbf97b28