Use URLRequestContextBuilderMojo to create the SystemURLRequestContext.

net/proxy/dhcp_proxy_script_fetcher_factory.h

 // Copyright (c) 2012 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 NET_PROXY_DHCP_PROXY_SCRIPT_FETCHER_FACTORY_H_
 #define NET_PROXY_DHCP_PROXY_SCRIPT_FETCHER_FACTORY_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 15 matching lines @@
 // client per machine (specifically per network interface card), and there
 // is an implicit state machine between the client and server, so adding a
 // second client to the machine would not be advisable (see e.g. some
 // discussion of what can happen at this URL:
 // http://www.net.princeton.edu/multi-dhcp-one-interface-handling.html).
 //
 // Therefore, we have platform-specific implementations, and so we use
 // this factory to select the right one.
 class NET_EXPORT DhcpProxyScriptFetcherFactory {
  public:
-  // Creates a new factory object with default settings.
   DhcpProxyScriptFetcherFactory();
 
+  virtual ~DhcpProxyScriptFetcherFactory();
+
   // url_request_context must be valid and its lifetime must exceed that of the
   // returned DhcpProxyScriptFetcher.
   //
   // Note that while a request is in progress, the fetcher may be holding a
   // reference to |url_request_context|. Be careful not to create cycles
   // between the fetcher and the context; you can break such cycles by calling
   // Cancel().
-  std::unique_ptr<DhcpProxyScriptFetcher> Create(
+  virtual std::unique_ptr<DhcpProxyScriptFetcher> Create(
       URLRequestContext* url_request_context);
 
-  // Attempts to enable/disable the DHCP WPAD feature.  Does nothing
-  // if |IsSupported()| returns false.
-  //
-  // The default is |enabled() == true|.
-  void set_enabled(bool enabled);
-
-  // Returns true if the DHCP WPAD feature is enabled.  Always returns
-  // false if |IsSupported()| is false.
-  bool enabled() const;
-
-  // Returns true if the DHCP WPAD feature is supported on the current
-  // operating system.
-  static bool IsSupported();
-
  private:
-  bool feature_enabled_;
-
   DISALLOW_COPY_AND_ASSIGN(DhcpProxyScriptFetcherFactory);
 };
 
 }  // namespace net
 
 #endif  // NET_PROXY_DHCP_PROXY_SCRIPT_FETCHER_FACTORY_H_