Mark the multiwindow divider as a trusted overlay.

Having it be untrusted breaks the permissions granting dialog in
multiwindow mode.

Bug: 28828041
Change-Id: I9193dbce7315ebaa205673edd4f406d0b72665c8
diff --git a/services/inputflinger/InputWindow.h b/services/inputflinger/InputWindow.h
index 0ac7fce..e243637 100644
--- a/services/inputflinger/InputWindow.h
+++ b/services/inputflinger/InputWindow.h
@@ -102,6 +102,7 @@
         TYPE_VOLUME_OVERLAY = FIRST_SYSTEM_WINDOW+20,
         TYPE_BOOT_PROGRESS = FIRST_SYSTEM_WINDOW+21,
         TYPE_MAGNIFICATION_OVERLAY = FIRST_SYSTEM_WINDOW+22,
+        TYPE_DOCK_DIVIDER = FIRST_SYSTEM_WINDOW+34,
         LAST_SYSTEM_WINDOW      = 2999,
     };