Backout Bug 1351860, r=backout

dom/html/HTMLFieldSetElement.h

@@ -50,6 +50,7 @@ public:
   virtual void RemoveChildAt(uint32_t aIndex, bool aNotify) override;
 
   // nsIFormControl
+  NS_IMETHOD_(uint32_t) GetType() const override { return NS_FORM_FIELDSET; }
   NS_IMETHOD Reset() override;
   NS_IMETHOD SubmitNamesValues(HTMLFormSubmission* aFormSubmission) override;
   virtual bool IsDisabledForEvents(EventMessage aMessage) override;