Modernize coding style in core/html/forms/.

Source/core/html/forms/RadioButtonGroupScope.h

Index: Source/core/html/forms/RadioButtonGroupScope.h
diff --git a/Source/core/html/forms/RadioButtonGroupScope.h b/Source/core/html/forms/RadioButtonGroupScope.h
index 88cd1b6e2bacc9c728fe81ece74cbe94d0ffb57e..af99f54080bb5d8998326e9658ccaf10a125da11 100644
--- a/Source/core/html/forms/RadioButtonGroupScope.h
+++ b/Source/core/html/forms/RadioButtonGroupScope.h
@@ -46,7 +46,7 @@ public:
     bool isInRequiredGroup(HTMLInputElement*) const;
 
 private:
-    typedef WillBeHeapHashMap<AtomicString, OwnPtrWillBeMember<RadioButtonGroup>, CaseFoldingHash> NameToGroupMap;
+    using NameToGroupMap = WillBeHeapHashMap<AtomicString, OwnPtrWillBeMember<RadioButtonGroup>, CaseFoldingHash>;
     OwnPtrWillBeMember<NameToGroupMap> m_nameToGroupMap;
 };