Debug the generic session restore failure.

chrome/browser/sessions/session_backend.h

 // Copyright (c) 2011 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_BACKEND_H_
 #define CHROME_BROWSER_SESSIONS_SESSION_BACKEND_H_
 
 #include <vector>
 
 #include "base/memory/ref_counted.h"
@@ skipping 103 matching lines @@
                             const std::vector<SessionCommand*>& commands);
 
   const BaseSessionService::SessionType type_;
 
   // Returns the path to the last file.
   FilePath GetLastSessionPath();
 
   // Returns the path to the current file.
   FilePath GetCurrentSessionPath();
 
+  // Writes data about session restore file cycling into preferences.
+  void WriteDebugData();
+
   // Directory files are relative to.
   const FilePath path_to_dir_;
 
   // Whether the previous target file is valid.
   bool last_session_valid_;
 
   // Handle to the target file.
   scoped_ptr<net::FileStream> current_session_file_;
 
   // Whether we've inited. Remember, the constructor is run on the
   // Main thread, all others on the IO thread, hence lazy initialization.
   bool inited_;
 
   // If true, the file is empty (no commands have been added to it).
   bool empty_file_;
 
   DISALLOW_COPY_AND_ASSIGN(SessionBackend);
 };
 
 #endif  // CHROME_BROWSER_SESSIONS_SESSION_BACKEND_H_