Bug 1213589 part.9 ContentEventHandler::ShouldBreakLineBefore() should return false if the content is unknown HTML element r=smaug

dom/html/HTMLUnknownElement.cpp

@@ -14,6 +14,9 @@ NS_IMPL_NS_NEW_HTML_ELEMENT(Unknown)
 namespace mozilla {
 namespace dom {
 
+NS_IMPL_ISUPPORTS_INHERITED(HTMLUnknownElement, nsGenericHTMLElement,
+                            HTMLUnknownElement)
+
 JSObject*
 HTMLUnknownElement::WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto)
 {