Allow ProxyConfigService to report "no configuration set"

net/proxy/polling_proxy_config_service.h

Index: net/proxy/polling_proxy_config_service.h
diff --git a/net/proxy/polling_proxy_config_service.h b/net/proxy/polling_proxy_config_service.h
index b4295ec10344d69f776b4eb4a4e405c1f5eca221..039a0c66bbb7eb98e5e8e463aa9ea744acbfcdd2 100644
--- a/net/proxy/polling_proxy_config_service.h
+++ b/net/proxy/polling_proxy_config_service.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 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.
 
@@ -6,8 +6,8 @@
 #define NET_PROXY_POLLING_PROXY_CONFIG_SERVICE_H_
 #pragma once
 
-#include "base/time.h"
 #include "base/ref_counted.h"
+#include "base/time.h"
 #include "net/proxy/proxy_config_service.h"
 
 namespace net {
@@ -22,7 +22,7 @@ class PollingProxyConfigService : public ProxyConfigService {
   // ProxyConfigService implementation:
   virtual void AddObserver(Observer* observer);
   virtual void RemoveObserver(Observer* observer);
-  virtual bool GetLatestProxyConfig(ProxyConfig* config);
+  virtual ConfigAvailability GetLatestProxyConfig(ProxyConfig* config);
   virtual void OnLazyPoll();
 
  protected: