Add handling to respect role attribute in AXObjects.

Source/modules/accessibility/AXMenuList.cpp

Index: Source/modules/accessibility/AXMenuList.cpp
diff --git a/Source/modules/accessibility/AXMenuList.cpp b/Source/modules/accessibility/AXMenuList.cpp
index 0d952812576efc79988f23692968ceeba5fbc3b9..bc690b07b93e564b996852061eed8b3860855570 100644
--- a/Source/modules/accessibility/AXMenuList.cpp
+++ b/Source/modules/accessibility/AXMenuList.cpp
@@ -42,6 +42,14 @@ PassRefPtr<AXMenuList> AXMenuList::create(LayoutMenuList* layoutObject, AXObject
     return adoptRef(new AXMenuList(layoutObject, axObjectCache));
 }
 
+AccessibilityRole AXMenuList::roleValue() const
+{
+    AccessibilityRole ariaRole = ariaRoleAttribute();
+    if (ariaRole != UnknownRole)
+        return ariaRole;
+    return PopUpButtonRole;
+}
+
 bool AXMenuList::press() const
 {
     LayoutMenuList* menuList = toLayoutMenuList(m_layoutObject);