Minor tweak to Session* to use base::Passed so ownership is clearer

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 40 matching lines @@
 
   // Moves the current file to the last file, and recreates the current file.
   //
   // NOTE: this is invoked before every command, and does nothing if we've
   // already Init'ed.
   void Init();
   bool inited() const { return inited_; }
 
   // Appends the specified commands to the current file. If reset_first is
   // true the the current file is recreated.
-  //
-  // NOTE: this deletes SessionCommands in commands as well as the supplied
-  // vector.
-  void AppendCommands(ScopedVector<SessionCommand>* commands, bool reset_first);
+  void AppendCommands(ScopedVector<SessionCommand> commands, bool reset_first);
 
   // Invoked from the service to read the commands that make up the last
   // session, invokes ReadLastSessionCommandsImpl to do the work.
   void ReadLastSessionCommands(
       const base::CancelableTaskTracker::IsCanceledCallback& is_canceled,
       const BaseSessionService::InternalGetCommandsCallback& callback);
 
   // Reads the commands from the last file.
   //
   // On success, the read commands are added to commands.
@@ skipping 55 matching lines @@
   // 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_