Fix bug in submenus opened from icon menus

Change-Id: I8b60ceefbccb5cad78d1b5c55702a2685a5f5382
diff --git a/core/java/com/android/internal/view/menu/IconMenuPresenter.java b/core/java/com/android/internal/view/menu/IconMenuPresenter.java
index 56128d4..d1b1dae 100644
--- a/core/java/com/android/internal/view/menu/IconMenuPresenter.java
+++ b/core/java/com/android/internal/view/menu/IconMenuPresenter.java
@@ -179,8 +179,10 @@
         @Override
         public void onCloseMenu(MenuBuilder menu, boolean allMenusAreClosing) {
             mOpenSubMenuId = 0;
-            mOpenSubMenu.dismiss();
-            mOpenSubMenu = null;
+            if (mOpenSubMenu != null) {
+                mOpenSubMenu.dismiss();
+                mOpenSubMenu = null;
+            }
         }
 
         @Override