Manual merge of ag/2319717

Bug: 62104030
Test: Manually tested as described in original commit msg.
Change-Id: Ie00bafa736c837881a258c9de10891b27c5baefd

src/com/android/settings/Utils.java

@@ -25,6 +25,7 @@ import android.annotation.Nullable;
 import android.app.ActivityManager;
 import android.app.AlertDialog;
 import android.app.AppGlobals;
+import android.app.AppOpsManager;
 import android.app.Dialog;
 import android.app.Fragment;
 import android.app.IActivityManager;
@@ -1272,6 +1273,20 @@ public final class Utils extends com.android.settingslib.Utils {
         return info.enabled ? R.string.installed : R.string.disabled;
     }
 
+    /**
+     * Control if other apps can display overlays. By default this is allowed. Be sure to
+     * re-enable overlays, as the effect is system-wide.
+     */
+    public static void setOverlayAllowed(Context context, IBinder token, boolean allowed) {
+        AppOpsManager appOpsManager = context.getSystemService(AppOpsManager.class);
+        if (appOpsManager != null) {
+            appOpsManager.setUserRestriction(AppOpsManager.OP_SYSTEM_ALERT_WINDOW,
+                    !allowed, token);
+            appOpsManager.setUserRestriction(AppOpsManager.OP_TOAST_WINDOW,
+                    !allowed, token);
+        }
+    }
+
     private static boolean isVolumeValid(VolumeInfo volume) {
         return (volume != null) && (volume.getType() == VolumeInfo.TYPE_PRIVATE)
                 && volume.isMountedReadable();