Remove lots of dead virtuals from Element.

sky/engine/core/dom/Element.h

Index: sky/engine/core/dom/Element.h
diff --git a/sky/engine/core/dom/Element.h b/sky/engine/core/dom/Element.h
index 39008e6b721e16cac72dcb1fac93d43708e64e61..68fc5904eb1de5af34d0a04e027b5818f49230a0 100644
--- a/sky/engine/core/dom/Element.h
+++ b/sky/engine/core/dom/Element.h
@@ -237,8 +237,6 @@ public:
 
     bool hasEquivalentAttributes(const Element* other) const;
 
-    virtual void copyNonAttributePropertiesFromElement(const Element&) { }
-
     virtual void attach(const AttachContext& = AttachContext()) override;
     virtual void detach(const AttachContext& = AttachContext()) override;
     virtual RenderObject* createRenderer(RenderStyle*);
@@ -329,21 +327,8 @@ public:
 
     DOMTokenList& classList();
 
-    virtual bool isFormControlElement() const { return false; }
-    virtual bool isOptionalFormControl() const { return false; }
-    virtual bool isRequiredFormControl() const { return false; }
-    virtual bool isDefaultButtonForForm() const { return false; }
-    virtual bool willValidate() const { return false; }
-    virtual bool isValidFormControlElement() { return false; }
-    virtual bool isInRange() const { return false; }
-    virtual bool isOutOfRange() const { return false; }
-
     virtual bool canContainRangeEndPoint() const override { return true; }
 
-    // Used for disabled form elements; if true, prevents mouse events from being dispatched
-    // to event listeners, and prevents DOMActivate events from being sent at all.
-    virtual bool isDisabledFormControl() const { return false; }
-
     void setCustomElementDefinition(PassRefPtr<CustomElementDefinition>);
     CustomElementDefinition* customElementDefinition() const;
 
@@ -504,11 +489,6 @@ template<typename T> inline const T* toElement(const Node* node)
 }
 template<typename T, typename U> inline T* toElement(const RefPtr<U>& node) { return toElement<T>(node.get()); }
 
-inline bool isDisabledFormControl(const Node* node)
-{
-    return node->isElementNode() && toElement(node)->isDisabledFormControl();
-}
-
 inline Element* Node::parentElement() const
 {
     ContainerNode* parent = parentNode();