Implementation for switching between recently used tabs using ctrl tilde or quoteleft.

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 1f856b5017d26249e70b4649392735998e78db00..8f9a7c34643311c266b9c711903a3a9fe04e911b 100644
--- a/chrome/browser/tabs/tab_strip_model.h
+++ b/chrome/browser/tabs/tab_strip_model.h
@@ -7,8 +7,10 @@
 #pragma once
 
 #include <vector>
+#include <list>
 
 #include "base/observer_list.h"
+#include "chrome/browser/tabs/tab_mru_list_manager.h"
 #include "chrome/browser/tabs/tab_strip_model_observer.h"
 #include "chrome/browser/tabs/tab_strip_selection_model.h"
 #include "content/public/browser/notification_observer.h"
@@ -435,6 +437,8 @@ class TabStripModel : public content::NotificationObserver {
 
   // Selects the last tab in the tab strip.
   void SelectLastTab();
+  // Selectd the next tab in MRU list.
+  void SelectNextMRUTab();
 
   // Swap adjacent tabs.
   void MoveTabNext();
@@ -598,6 +602,12 @@ class TabStripModel : public content::NotificationObserver {
   void ForgetOpenersAndGroupsReferencing(
       const content::NavigationController* tab);
 
+  // Tab Strip Most Recently used list management functions.
+  void TabMRUListRemoveContents(TabContentsWrapper* removed_contents);
+  void TabMRUListActivateContents(TabContentsWrapper* new_contents);
+  void TabMRUListReplaceContents(TabContentsWrapper* old_contents,
+                                 TabContentsWrapper* new_contents);
+
   // Our delegate.
   TabStripModelDelegate* delegate_;
 
@@ -678,6 +688,10 @@ class TabStripModel : public content::NotificationObserver {
   // selection should move when a Tab is closed.
   TabStripModelOrderController* order_controller_;
 
+  // List manager that maintains the tab indices in the most recently
+  // visited order.
+  TabMRUListManager tab_mru_list_manager_;
+
   // Our observers.
   typedef ObserverList<TabStripModelObserver> TabStripModelObservers;
   TabStripModelObservers observers_;