Implement :valid and :invalid pseudoclass for <form> (resubmitting)

Source/core/html/HTMLFormControlElement.h

Index: Source/core/html/HTMLFormControlElement.h
diff --git a/Source/core/html/HTMLFormControlElement.h b/Source/core/html/HTMLFormControlElement.h
index 9cc28bb21388a98a77e744b1100a2b6a2a2bafa3..4904ed4277696ea1cf8d3a5303831c933a472a73 100644
--- a/Source/core/html/HTMLFormControlElement.h
+++ b/Source/core/html/HTMLFormControlElement.h
@@ -85,6 +85,8 @@ public:
     virtual void setActivatedSubmit(bool) { }
 
     virtual bool willValidate() const override;
+    virtual bool matchesValidityPseudoClasses() const override;
+
     void updateVisibleValidationMessage();
     void hideVisibleValidationMessage();
     bool checkValidity(WillBeHeapVector<RefPtrWillBeMember<FormAssociatedElement> >* unhandledInvalidControls = 0);
@@ -121,6 +123,8 @@ protected:
     virtual void attach(const AttachContext& = AttachContext()) override;
     virtual InsertionNotificationRequest insertedInto(ContainerNode*) override;
     virtual void removedFrom(ContainerNode*) override;
+    virtual void willChangeForm() override;
+    virtual void didChangeForm() override;
     virtual void didMoveToNewDocument(Document& oldDocument) override;
 
     virtual bool supportsFocus() const override;
@@ -152,12 +156,15 @@ private:
     virtual short tabIndex() const override final;
 
     virtual bool isDefaultButtonForForm() const override final;
-    virtual bool isValidFormControlElement() override final;
+    virtual bool isValidElement() override final;
     void updateAncestorDisabledState() const;
 
     bool isValidationMessageVisible() const;
     ValidationMessageClient* validationMessageClient() const;
 
+    // Requests validity recalc for the form owner, if one exists.
+    void formOwnerSetNeedsValidityCheck();
+
     bool m_disabled : 1;
     bool m_isAutofilled : 1;
     bool m_isReadOnly : 1;