Attempt at fixing crash in tab code. It appears that we end up in a

chrome/browser/tabs/tab_strip_model.h

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_TABS_TAB_STRIP_MODEL_H_
 #define CHROME_BROWSER_TABS_TAB_STRIP_MODEL_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 462 matching lines @@
                              bool select_after_move);
 
   // Returns true if the tab represented by the specified data has an opener
   // that matches the specified one. If |use_group| is true, then this will
   // fall back to check the group relationship as well.
   struct TabContentsData;
   static bool OpenerMatches(const TabContentsData* data,
                             const NavigationController* opener,
                             bool use_group);
 
+  // Sets the group/opener of any tabs that reference |tab| to NULL.
+  void ForgetOpenersAndGroupsReferencing(const NavigationController* tab);
+
   // Our delegate.
   TabStripModelDelegate* delegate_;
 
   // A hunk of data representing a TabContents and (optionally) the
   // NavigationController that spawned it. This memory only sticks around while
   // the TabContents is in the current TabStripModel, unless otherwise
   // specified in code.
   struct TabContentsData {
     explicit TabContentsData(TabContentsWrapper* a_contents)
         : contents(a_contents),
@@ skipping 69 matching lines @@
   typedef ObserverList<TabStripModelObserver> TabStripModelObservers;
   TabStripModelObservers observers_;
 
   // A scoped container for notification registries.
   NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(TabStripModel);
 };
 
 #endif  // CHROME_BROWSER_TABS_TAB_STRIP_MODEL_H_