Multi-tab: Adding new Notification when tab selection changes.

chrome/browser/tabs/tab_strip_model.h

 // Copyright (c) 2011 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 507 matching lines @@
   // If the TabContentsWrapper at |to_index| differs from |old_contents|
   // notifies observers.
   void NotifyTabSelectedIfChanged(TabContentsWrapper* old_contents,
                                   int to_index,
                                   bool user_gesture);
 
   // Notifies the observers the active tab changed. |old_active_index| gives
   // the old active index.
   void NotifyActiveTabChanged(int old_active_index);
 
+  // Notifies the observers that the tab selection has changed. |model| is a
+  // snapshot of the selection_model_ before the change.
+  void NotifySelectionChanged(const TabStripSelectionModel& model);
+
   // Returns the number of New Tab tabs in the TabStripModel.
   int GetNewTabCount() const;
 
   // Selects either the next tab (|foward| is true), or the previous tab
   // (|forward| is false).
   void SelectRelativeTab(bool forward);
 
   // Does the work of MoveTabContentsAt. This has no checks to make sure the
   // position is valid, those are done in MoveTabContentsAt.
   void MoveTabContentsAtImpl(int index,
@@ skipping 96 matching lines @@
 
   // A scoped container for notification registries.
   NotificationRegistrar registrar_;
 
   TabStripSelectionModel selection_model_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(TabStripModel);
 };
 
 #endif  // CHROME_BROWSER_TABS_TAB_STRIP_MODEL_H_