Use URLRequestContextBuilderMojo to create the SystemURLRequestContext.

net/proxy/dhcp_proxy_script_fetcher_factory.h

Index: net/proxy/dhcp_proxy_script_fetcher_factory.h
diff --git a/net/proxy/dhcp_proxy_script_fetcher_factory.h b/net/proxy/dhcp_proxy_script_fetcher_factory.h
index bad2d9d9ff7abb6b28a64c62e872bfb3794d576e..e80c8b69b97704655921f0f614772154f9fff546 100644
--- a/net/proxy/dhcp_proxy_script_fetcher_factory.h
+++ b/net/proxy/dhcp_proxy_script_fetcher_factory.h
@@ -33,9 +33,10 @@ class URLRequestContext;
 // 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.
   //
@@ -43,26 +44,10 @@ class NET_EXPORT DhcpProxyScriptFetcherFactory {
   // 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);
 };