Bug 530652 - Some sites not render flash. Fixing mistake introduced in last push r=biesinger

layout/generic/nsObjectFrame.cpp

@@ -5794,7 +5794,7 @@ nsPluginInstanceOwner::SetAbsoluteScreenPosition(nsIDOMElement* element,
   PRBool simpleImageRender = PR_FALSE;
   mInstance->GetValueFromPlugin(NPPVpluginWindowlessLocalBool,
                                 &simpleImageRender);
-  if (mInstance)
+  if (simpleImageRender)
     NativeImageDraw();
   return NS_OK;
 }