Implement computedRole and computedName (behind a flag)

Source/modules/accessibility/AXObject.h

Index: Source/modules/accessibility/AXObject.h
diff --git a/Source/modules/accessibility/AXObject.h b/Source/modules/accessibility/AXObject.h
index 0e2c5c10eaf158cca93cd3e5ac5a7afb46bf33c4..d627d545e18c344d41b9db52f078fc6268978ba1 100644
--- a/Source/modules/accessibility/AXObject.h
+++ b/Source/modules/accessibility/AXObject.h
@@ -40,6 +40,7 @@
 namespace blink {
 
 class AXObject;
+class AXObjectCache;
 class AXObjectCacheImpl;
 class Element;
 class FrameView;
@@ -52,6 +53,7 @@ class Widget;
 typedef unsigned AXID;
 
 enum AccessibilityRole {
+    NoRole = 0,
     AlertDialogRole = 1,
     AlertRole,
     AnnotationRole,
@@ -167,6 +169,7 @@ enum AccessibilityRole {
     UserInterfaceTooltipRole,
     WebAreaRole,
     WindowRole,
+    NumRoles
 };
 
 enum AccessibilityTextSource {
@@ -577,6 +580,7 @@ public:
     static bool isARIAInput(AccessibilityRole);
     static AccessibilityRole ariaRoleToWebCoreRole(const String&);
     static IntRect boundingBoxForQuads(RenderObject*, const Vector<FloatQuad>&);
+    static const AtomicString& roleName(const AccessibilityRole);
 
 protected:
     AXID m_id;