The dialog can only be requested if the package of the controls provider is
currently in the foreground.
This is accomplished by querying Activity Manager about the
UidImportance of that package. Added
android.permission.PACKAGE_USAGE_STATS to SystemUI for this.
Test: atest
Test: manual
Fixes: 149410221
Change-Id: Ifdf479d8dbc70502da95d362e3bfd60ad3c561fb
04e7bdef04