Remove Attr child nodes (making Attr a Node, not a ContainerNode)

Source/core/dom/Element.h

Index: Source/core/dom/Element.h
diff --git a/Source/core/dom/Element.h b/Source/core/dom/Element.h
index 9ea7ec5c79c8d55cf252ef2bb72a49835df7d578..cba660ac9a2ea9bc262319c8f58af270636fa720 100644
--- a/Source/core/dom/Element.h
+++ b/Source/core/dom/Element.h
@@ -253,8 +253,6 @@ public:
 
     void scheduleSVGFilterLayerUpdateHack();
 
-    void normalizeAttributes();
-
     void setBooleanAttribute(const QualifiedName& name, bool);
 
     virtual const StylePropertySet* additionalPresentationAttributeStyle() { return nullptr; }
@@ -590,9 +588,6 @@ private:
     virtual void didAddUserAgentShadowRoot(ShadowRoot&) { }
     virtual bool alwaysCreateUserAgentShadowRoot() const { return false; }
 
-    // FIXME: Remove the need for Attr to call willModifyAttribute/didModifyAttribute.
-    friend class Attr;
-
     enum SynchronizationOfLazyAttribute { NotInSynchronizationOfLazyAttribute = 0, InSynchronizationOfLazyAttribute };
 
     void didAddAttribute(const QualifiedName&, const AtomicString&);