Bug 1553705 - Use a cheaper to compute state key for parser inserted form controls. r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D32259

dom/html/HTMLButtonElement.cpp

@@ -54,7 +54,7 @@ static const nsAttrValue::EnumTable* kButtonDefaultType = &kButtonTypeTable[2];
 HTMLButtonElement::HTMLButtonElement(
     already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo,
     FromParser aFromParser)
-    : nsGenericHTMLFormElementWithState(std::move(aNodeInfo),
+    : nsGenericHTMLFormElementWithState(std::move(aNodeInfo), aFromParser,
                                         kButtonDefaultType->value),
       mDisabledChanged(false),
       mInInternalActivate(false),
@@ -345,8 +345,8 @@ HTMLButtonElement::SubmitNamesValues(HTMLFormSubmission* aFormSubmission) {
 }
 
 void HTMLButtonElement::DoneCreatingElement() {
+  GenerateStateKey();
   if (!mInhibitStateRestoration) {
-    GenerateStateKey();
     RestoreFormControlState();
   }
 }