Virtual destructors should have virtual keyword.

content/plugin/npobject_stub.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.
 //
 // A class that receives IPC messages from an NPObjectProxy and calls the real
 // NPObject.
 
 #ifndef CONTENT_PLUGIN_NPOBJECT_STUB_H_
 #define CONTENT_PLUGIN_NPOBJECT_STUB_H_
 #pragma once
@@ skipping 18 matching lines @@
 class NPObjectStub : public IPC::Channel::Listener,
                      public IPC::Message::Sender,
                      public base::SupportsWeakPtr<NPObjectStub>,
                      public NPObjectBase {
  public:
   NPObjectStub(NPObject* npobject,
                PluginChannelBase* channel,
                int route_id,
                gfx::NativeViewId containing_window,
                const GURL& page_url);
-  ~NPObjectStub();
+  virtual ~NPObjectStub();
 
   // IPC::Message::Sender implementation:
   virtual bool Send(IPC::Message* msg);
 
   // Called when the plugin widget that this NPObject came from is destroyed.
   // This is needed because the renderer calls NPN_DeallocateObject on the
   // window script object on destruction to avoid leaks.
   void OnPluginDestroyed();
 
   // NPObjectBase implementation.
@@ skipping 36 matching lines @@
   NPObject* npobject_;
   scoped_refptr<PluginChannelBase> channel_;
   int route_id_;
   gfx::NativeViewId containing_window_;
 
   // The url of the main frame hosting the plugin.
   GURL page_url_;
 };
 
 #endif  // CONTENT_PLUGIN_NPOBJECT_STUB_H_