Issue #2678 - Stop using EnsureExpandoObject in codegen code when we just want to preserver the wrapper for a DOM proxy.

dom/html/HTMLTableElement.cpp

@@ -48,6 +48,7 @@ public:
 
   // nsWrapperCache
   using nsWrapperCache::GetWrapperPreserveColor;
+  using nsWrapperCache::PreserveWrapper;
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 protected:
   virtual ~TableRowsCollection();
@@ -56,6 +57,10 @@ protected:
   {
     return nsWrapperCache::GetWrapperPreserveColor();
   }
+  virtual void PreserveWrapperInternal(nsISupports* aScriptObjectHolder) override
+  {
+    nsWrapperCache::PreserveWrapper(aScriptObjectHolder);
+  }
 
   // Those rows that are not in table sections
   HTMLTableElement* mParent;