Fix bug: AppShell: CHECK failure in PeerConnection init.

content/shell/browser/shell_url_request_context_getter.h

 // Copyright 2013 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 CONTENT_SHELL_BROWSER_SHELL_URL_REQUEST_CONTEXT_GETTER_H_
 #define CONTENT_SHELL_BROWSER_SHELL_URL_REQUEST_CONTEXT_GETTER_H_
 
 #include "base/compiler_specific.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
@@ skipping 26 matching lines @@
       base::MessageLoop* file_loop,
       ProtocolHandlerMap* protocol_handlers,
       URLRequestInterceptorScopedVector request_interceptors,
       net::NetLog* net_log);
 
   // net::URLRequestContextGetter implementation.
   virtual net::URLRequestContext* GetURLRequestContext() override;
   virtual scoped_refptr<base::SingleThreadTaskRunner>
       GetNetworkTaskRunner() const override;
 
+  // Used by subclasses to create their own implementation of NetworkDelegate.
+  virtual net::NetworkDelegate* CreateNetworkDelegate();
+
   net::HostResolver* host_resolver();
 
  protected:
   virtual ~ShellURLRequestContextGetter();
 
  private:
   bool ignore_certificate_errors_;
   base::FilePath base_path_;
   base::MessageLoop* io_loop_;
   base::MessageLoop* file_loop_;
   net::NetLog* net_log_;
 
   scoped_ptr<net::ProxyConfigService> proxy_config_service_;
   scoped_ptr<net::NetworkDelegate> network_delegate_;
   scoped_ptr<net::URLRequestContextStorage> storage_;
   scoped_ptr<net::URLRequestContext> url_request_context_;
   ProtocolHandlerMap protocol_handlers_;
   URLRequestInterceptorScopedVector request_interceptors_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellURLRequestContextGetter);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_SHELL_BROWSER_SHELL_URL_REQUEST_CONTEXT_GETTER_H_