fix build issue on Linux with GCC 4.1.2...

webkit/glue/webplugin.h

 // Copyright (c) 2006-2008 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 WEBKIT_GLUE_WEBPLUGIN_H__
 #define WEBKIT_GLUE_WEBPLUGIN_H__
 
 #include <string>
 #include <vector>
 
@@ skipping 115 matching lines @@
                                 bool notify, const char* url,
                                 void* notify_data, bool popups_allowed) = 0;
 
  private:
   DISALLOW_EVIL_CONSTRUCTORS(WebPlugin);
 };
 
 // Simpler version of ResourceHandleClient that lends itself to proxying.
 class WebPluginResourceClient {
  public:
+  virtual ~WebPluginResourceClient() {}
   virtual void WillSendRequest(const GURL& url) = 0;
   virtual void DidReceiveResponse(const std::string& mime_type,
                                   const std::string& headers,
                                   uint32 expected_length,
                                   uint32 last_modified,
                                   bool* cancel) = 0;
   virtual void DidReceiveData(const char* buffer, int length) = 0;
   virtual void DidFinishLoading() = 0;
   virtual void DidFail() = 0;
 };
 
 
 #endif  // #ifndef WEBKIT_GLUE_WEBPLUGIN_H__