Clear session-only data when all browser windows are closed.

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 184 matching lines @@
 
   // Overridden from BaseSessionService because we want some UMA reporting on
   // session update activities.
   virtual void Save() OVERRIDE;
 
  private:
   // Allow tests to access our innards for testing purposes.
   FRIEND_TEST_ALL_PREFIXES(SessionServiceTest, RestoreActivation1);
   FRIEND_TEST_ALL_PREFIXES(SessionServiceTest, RestoreActivation2);
   FRIEND_TEST_ALL_PREFIXES(NoStartupWindowTest, DontInitSessionServiceForApps);
+  friend class BetterSessionRestoreTest;
 
   typedef std::map<SessionID::id_type, std::pair<int, int> > IdToRange;
   typedef std::map<SessionID::id_type, SessionTab*> IdToSessionTab;
   typedef std::map<SessionID::id_type, SessionWindow*> IdToSessionWindow;
 
 
   // These types mirror Browser::Type, but are re-defined here because these
   // specific enumeration _values_ are written into the session database and
   // are needed to maintain forward compatibility.
   // Note that we only store browsers of type TYPE_TABBED and TYPE_POPUP.
@@ skipping 281 matching lines @@
   const base::TimeDelta save_delay_in_hrs_;
 
   // For browser_tests, since we want to simulate the browser shutting down
   // without quitting.
   bool force_browser_not_alive_with_no_windows_;
 
   DISALLOW_COPY_AND_ASSIGN(SessionService);
 };
 
 #endif  // CHROME_BROWSER_SESSIONS_SESSION_SERVICE_H_