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

chrome/browser/tabs/tab_strip_model.h

Index: chrome/browser/tabs/tab_strip_model.h
diff --git a/chrome/browser/tabs/tab_strip_model.h b/chrome/browser/tabs/tab_strip_model.h
index e711b493a90d0bd02f7b1d5a2ee5dd4d66f52313..c16c37c465b8456e22193ec09744884deed0d817 100644
--- a/chrome/browser/tabs/tab_strip_model.h
+++ b/chrome/browser/tabs/tab_strip_model.h
@@ -525,6 +525,15 @@ class TabStripModel : public NotificationObserver {
   // the old active index.
   void NotifyActiveTabChanged(int old_active_index);
 
+  // Notifies the observers that the tab selection has changed. |model| is a
+  // snapshot of |selection_model_|_ before the change.
+  void NotifySelectionChanged(const TabStripSelectionModel& model);
+
+  // Notifies the observers only if the active tab or the tab selection has
+  // changed, by calling NotifyActiveTabChanged and/or NotifySelectionChanged.
+  // |model| is a snapshot of |selection_model_|_ before the change.
+  void NotifyIfActiveOrSelectionChanged(const TabStripSelectionModel& model);
+
   // Returns the number of New Tab tabs in the TabStripModel.
   int GetNewTabCount() const;