Don't show icons for top level menus unless forced.

Prior to this CL, the cascading implementation would evaluate the
contents of the menu to determine whether to show an icon for this case.
However, the policy we have upheld is that top level menus should
never show an icon for this case. (Unless setForceShowIcon(true) was
called.)

Bug: 28275346
Change-Id: I09423596d49742aa7a9ba7245702c099581c0b48
diff --git a/core/java/com/android/internal/view/menu/MenuPopupHelper.java b/core/java/com/android/internal/view/menu/MenuPopupHelper.java
index 1f1e594..9f029ad 100644
--- a/core/java/com/android/internal/view/menu/MenuPopupHelper.java
+++ b/core/java/com/android/internal/view/menu/MenuPopupHelper.java
@@ -104,6 +104,9 @@
      */
     public void setForceShowIcon(boolean forceShowIcon) {
         mForceShowIcon = forceShowIcon;
+        if (mPopup != null) {
+            mPopup.setForceShowIcon(forceShowIcon);
+        }
     }
 
     /**