[Session restore] Add MRU logic to loading of background pages.

chrome/browser/sessions/session_service.h

 // Copyright (c) 2012 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_SESSIONS_SESSION_SERVICE_H_
 #define CHROME_BROWSER_SESSIONS_SESSION_SERVICE_H_
 
 #include <map>
 #include <string>
 
@@ skipping 183 matching lines @@
   // Sets the user agent override of the specified tab.
   void SetTabUserAgentOverride(const SessionID& window_id,
                                const SessionID& tab_id,
                                const std::string& user_agent_override);
 
   // Sets the application extension id of the specified tab.
   void SetTabExtensionAppID(const SessionID& window_id,
                             const SessionID& tab_id,
                             const std::string& extension_app_id);
 
+  // Sets the last active time of the tab.
+  void SetLastActiveTime(const SessionID& window_id,
+                         const SessionID& tab_id,
+                         base::TimeTicks last_active_time);
+
   // Callback from GetLastSession.
   // The second parameter is the id of the window that was last active.
   typedef base::Callback<void(ScopedVector<sessions::SessionWindow>,
                          SessionID::id_type)> SessionCallback;
 
   // Fetches the contents of the last session, notifying the callback when
   // done. If the callback is supplied an empty vector of SessionWindows
   // it means the session could not be restored.
   base::CancelableTaskTracker::TaskId GetLastSession(
       const SessionCallback& callback,
@@ skipping 177 matching lines @@
   // For browser_tests, since we want to simulate the browser shutting down
   // without quitting.
   bool force_browser_not_alive_with_no_windows_;
 
   base::WeakPtrFactory<SessionService> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SessionService);
 };
 
 #endif  // CHROME_BROWSER_SESSIONS_SESSION_SERVICE_H_