Allow ProxyService to share URLRequestContext with everything else.

net/proxy/dhcp_proxy_script_fetcher.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_H_
 #define NET_PROXY_DHCP_PROXY_SCRIPT_FETCHER_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/strings/string16.h"
@@ skipping 44 matching lines @@
   // If the request is cancelled (either using the "Cancel()" method or by
   // deleting |this|), then no callback is invoked.
   //
   // Only one fetch is allowed to be outstanding at a time.
   virtual int Fetch(base::string16* utf16_text,
                     const CompletionCallback& callback) = 0;
 
   // Aborts the in-progress fetch (if any).
   virtual void Cancel() = 0;
 
+  // Fails the in-progress fetch (if any) and future requests will fail
+  // immediately. Must be called before the URLRequestContext the fetcher was
+  // created with is torn down.
+  virtual void OnShutdown() = 0;
+
   // After successful completion of |Fetch()|, this will return the URL
   // retrieved from DHCP.  It is reset if/when |Fetch()| is called again.
   virtual const GURL& GetPacURL() const = 0;
 
   // Intended for unit tests only, so they can test that factories return
   // the right types under given circumstances.
   virtual std::string GetFetcherName() const;
 
  protected:
   DhcpProxyScriptFetcher();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(DhcpProxyScriptFetcher);
 };
 
 // A do-nothing retriever, always returns synchronously with
 // ERR_NOT_IMPLEMENTED result and empty text.
 class NET_EXPORT_PRIVATE DoNothingDhcpProxyScriptFetcher
     : public DhcpProxyScriptFetcher {
  public:
   DoNothingDhcpProxyScriptFetcher();
   ~DoNothingDhcpProxyScriptFetcher() override;
 
   int Fetch(base::string16* utf16_text,
             const CompletionCallback& callback) override;
   void Cancel() override;
+  void OnShutdown() override;
   const GURL& GetPacURL() const override;
 
  private:
   GURL gurl_;
   DISALLOW_COPY_AND_ASSIGN(DoNothingDhcpProxyScriptFetcher);
 };
 
 }  // namespace net
 
 #endif  // NET_PROXY_DHCP_PROXY_SCRIPT_FETCHER_H_