Remove the implicit fallback to DIRECT when proxies fail. This better matches...

net/proxy/proxy_list.h

 // Copyright (c) 2006-2008 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_LIST_H_
 #define NET_PROXY_PROXY_LIST_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 14 matching lines @@
   // Set the proxy list to a single entry, |proxy_server|.
   void SetSingleProxyServer(const ProxyServer& proxy_server);
 
   // Remove all proxies known to be bad from the proxy list.
   void RemoveBadProxies(const ProxyRetryInfoMap& proxy_retry_info);
 
   // Delete any entry which doesn't have one of the specified proxy schemes.
   // |scheme_bit_field| is a bunch of ProxyServer::Scheme bitwise ORed together.
   void RemoveProxiesWithoutScheme(int scheme_bit_field);
 
-  // Returns the first valid proxy server in the list.
-  ProxyServer Get() const;
+  // Returns true if there is nothing left in the ProxyList.
+  bool IsEmpty() const;
+
+  // Returns the first proxy server in the list. It is only valid to call
+  // this if !IsEmpty().
+  const ProxyServer& Get() const;
 
   // Set the list by parsing the pac result |pac_string|.
   // Some examples for |pac_string|:
   //   "DIRECT"
   //   "PROXY foopy1"
   //   "PROXY foopy1; SOCKS4 foopy2:1188"
   void SetFromPacString(const std::string& pac_string);
 
   // Returns a PAC-style semicolon-separated list of valid proxy servers.
   // For example: "PROXY xxx.xxx.xxx.xxx:xx; SOCKS yyy.yyy.yyy:yy".
   std::string ToPacString() const;
 
   // Marks the current proxy server as bad and deletes it from the list.  The
   // list of known bad proxies is given by proxy_retry_info.  Returns true if
   // there is another server available in the list.
   bool Fallback(ProxyRetryInfoMap* proxy_retry_info);
 
  private:
   // List of proxies.
   std::vector<ProxyServer> proxies_;
 };
 
 }  // namespace net
 
 #endif  // NET_PROXY_PROXY_LIST_H_