Allow ProxyConfigService to report "no configuration set"

net/proxy/proxy_config_service_fixed.h

-// Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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_PROXY_CONFIG_SERVICE_FIXED_H_
 #define NET_PROXY_PROXY_CONFIG_SERVICE_FIXED_H_
 #pragma once
 
 #include "net/base/net_errors.h"
 #include "net/proxy/proxy_config.h"
 #include "net/proxy/proxy_config_service.h"
 
 namespace net {
 
 // Implementation of ProxyConfigService that returns a fixed result.
 class ProxyConfigServiceFixed : public ProxyConfigService {
  public:
   explicit ProxyConfigServiceFixed(const ProxyConfig& pc);
   virtual ~ProxyConfigServiceFixed();
 
   // ProxyConfigService methods:
   virtual void AddObserver(Observer* observer) {}
   virtual void RemoveObserver(Observer* observer) {}
-  virtual bool GetLatestProxyConfig(ProxyConfig* config);
+  virtual ConfigAvailability GetLatestProxyConfig(ProxyConfig* config);
 
  private:
   ProxyConfig pc_;
 };
 
 }  // namespace net
 
 #endif  // NET_PROXY_PROXY_CONFIG_SERVICE_FIXED_H_