Use C++11 features in core/html

Source/core/html/HTMLFormControlElement.cpp

Index: Source/core/html/HTMLFormControlElement.cpp
diff --git a/Source/core/html/HTMLFormControlElement.cpp b/Source/core/html/HTMLFormControlElement.cpp
index 6605a6d7de08c0626db248818e31c90a55d09c40..02555ac588f08734e86d00d63823419f11815e9e 100644
--- a/Source/core/html/HTMLFormControlElement.cpp
+++ b/Source/core/html/HTMLFormControlElement.cpp
@@ -490,12 +490,12 @@ ValidationMessageClient* HTMLFormControlElement::validationMessageClient() const
 {
     Page* page = document().page();
     if (!page)
-        return 0;
+        return nullptr;
 
     return &page->validationMessageClient();
 }
 
-bool HTMLFormControlElement::checkValidity(WillBeHeapVector<RefPtrWillBeMember<HTMLFormControlElement> >* unhandledInvalidControls, CheckValidityEventBehavior eventBehavior)
+bool HTMLFormControlElement::checkValidity(WillBeHeapVector<RefPtrWillBeMember<HTMLFormControlElement>>* unhandledInvalidControls, CheckValidityEventBehavior eventBehavior)
 {
     if (!willValidate() || isValidElement())
         return true;
@@ -599,7 +599,7 @@ bool HTMLFormControlElement::isDefaultButtonForForm() const
 HTMLFormControlElement* HTMLFormControlElement::enclosingFormControlElement(Node* node)
 {
     if (!node)
-        return 0;
+        return nullptr;
     return Traversal<HTMLFormControlElement>::firstAncestorOrSelf(*node);
 }