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 497 matching lines @@
   //
   // The boolean parameter create_historical_tab controls whether to
   // record these tabs and their history for reopening recently closed
   // tabs.
   void InternalCloseTab(TabContentsWrapper* contents,
                         int index,
                         bool create_historical_tabs);
 
   TabContentsWrapper* GetContentsAt(int index) const;
 
-  // 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 if the active tab or the tab selection has changed.
+  // If |old_contents| is non-null a TabDeactivated notification is sent right
+  // before sending ActiveTabChanged notification. |old_model| is a snapshot of
+  // |selection_model_| before the change.
+  // Note: This function might end up sending 0 to 3 notifications in the
+  // following order: TabDeactivated, ActiveTabChanged, TabSelectionChanged.
+  void NotifyIfActiveOrSelectionChanged(
+      TabContentsWrapper* old_contents,
+      bool user_gesture,
+      const TabStripSelectionModel& old_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.
@@ skipping 97 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_