| Index: chrome/browser/tab_contents/navigation_controller.cc | 
| =================================================================== | 
| --- chrome/browser/tab_contents/navigation_controller.cc	(revision 68655) | 
| +++ chrome/browser/tab_contents/navigation_controller.cc	(working copy) | 
| @@ -980,8 +980,10 @@ | 
| // Take over the session id from source. | 
| session_id_ = source->session_id_; | 
|  | 
| -  // Reset source's session id as we're taking it over. | 
| -  source->session_id_.clear(); | 
| +  // Reset source's session id as we're taking it over. We give it a new id in | 
| +  // case source is added later on, which can happen with instant enabled if the | 
| +  // tab has a before unload handler. | 
| +  source->session_id_ = SessionID(); | 
| } | 
|  | 
| void NavigationController::PruneAllButActive() { | 
|  |