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..5bfab2cbfe02cec1fc5a126d25c2d4eabe0d9a91 100644
--- a/chrome/browser/tabs/tab_strip_model.h
+++ b/chrome/browser/tabs/tab_strip_model.h
@@ -523,7 +523,17 @@ class TabStripModel : public NotificationObserver {
 
   // Notifies the observers the active tab changed. |old_active_index| gives
   // the old active index.
-  void NotifyActiveTabChanged(int old_active_index);
+  void NotifyActiveTabChanged(int old_active_index, bool user_gesture);
+
+  // 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,
+                                        bool user_gesture);
 
   // Returns the number of New Tab tabs in the TabStripModel.
   int GetNewTabCount() const;