ViewRootImpl: Initialize sysui visibility

Fixes a bug where the sysui visibility flags
were not dispatched when they changed if the
visibility changes the first time to a zero
value.

Change-Id: I4d6c990ca493b144f24c75e95b4ff18c4c0a029c
Fixes: 30259249

core/java/android/view/View.java

@@ -22927,7 +22927,7 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
         /**
          * Last global system UI visibility reported by the window manager.
          */
-        int mGlobalSystemUiVisibility;
+        int mGlobalSystemUiVisibility = -1;
 
         /**
          * True if a view in this hierarchy has an OnSystemUiVisibilityChangeListener