Make WindowList.addFirst() public

addFirst() will become a public method in ArrayList. The overriding
method needs to public as well.

Bug: 320460092
Test: m droid
Change-Id: I6960b2eca186214e946dadece22e68ca36f31bff
diff --git a/services/core/java/com/android/server/wm/WindowList.java b/services/core/java/com/android/server/wm/WindowList.java
index dfeba40..1e888f5 100644
--- a/services/core/java/com/android/server/wm/WindowList.java
+++ b/services/core/java/com/android/server/wm/WindowList.java
@@ -24,7 +24,7 @@
  */
 class WindowList<E> extends ArrayList<E> {
 
-    void addFirst(E e) {
+    public void addFirst(E e) {
         add(0, e);
     }