Virtual destructors should have virtual keyword.

chrome/browser/sync/notifier/chrome_system_resources.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.
 //
 // Simple system resources class that uses the current message loop
 // for scheduling.  Assumes the current message loop is already
 // running.
 
 #ifndef CHROME_BROWSER_SYNC_NOTIFIER_CHROME_SYSTEM_RESOURCES_H_
 #define CHROME_BROWSER_SYNC_NOTIFIER_CHROME_SYSTEM_RESOURCES_H_
 #pragma once
 
 #include <set>
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "base/task.h"
 #include "base/threading/non_thread_safe.h"
 #include "chrome/browser/sync/notifier/state_writer.h"
 #include "google/cacheinvalidation/invalidation-client.h"
 
 namespace sync_notifier {
 
 class ChromeSystemResources : public invalidation::SystemResources {
  public:
   explicit ChromeSystemResources(StateWriter* state_writer);
 
-  ~ChromeSystemResources();
+  virtual ~ChromeSystemResources();
 
   // invalidation::SystemResources implementation.
 
   virtual invalidation::Time current_time();
 
   virtual void StartScheduler();
 
   virtual void StopScheduler();
 
   virtual void ScheduleWithDelay(invalidation::TimeDelta delay,
@@ skipping 31 matching lines @@
   void RunPostedTask(invalidation::Closure* task);
 
   // Runs the given storage callback with "true" and deletes it.
   void RunAndDeleteStorageCallback(
       invalidation::StorageCallback* callback);
 };
 
 }  // namespace sync_notifier
 
 #endif  // CHROME_BROWSER_SYNC_NOTIFIER_CHROME_SYSTEM_RESOURCES_H_