Policy: Add ProxyMode and deprecate ProxyServerMode.

chrome/browser/prefs/proxy_prefs.h

 // Copyright (c) 2010 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 CHROME_BROWSER_PREFS_PROXY_PREFS_H_
 #define CHROME_BROWSER_PREFS_PROXY_PREFS_H_
 #pragma once
 
 #include <string>
 
@@ skipping 18 matching lines @@
   // Use the settings specified in kProxyServer and kProxyBypassList.
   MODE_FIXED_SERVERS = 3,
 
   // The system's proxy settings are used, other proxy preferences are
   // ignored.
   MODE_SYSTEM = 4,
 
   kModeCount
 };
 
+// Constants for string values used to specify the proxy mode through externally
+// visible APIs, e.g. through policy or the proxy extension API.
+extern const char kDirectProxyModeName[];
+extern const char kAutoDetectProxyModeName[];
+extern const char kPacScriptProxyModeName[];
+extern const char kFixedServersProxyModeName[];
+extern const char kSystemProxyModeName[];
+
 bool IntToProxyMode(int in_value, ProxyMode* out_value);
 bool StringToProxyMode(const std::string& in_value,
                        ProxyMode* out_value);
 
 }  // namespace ProxyPrefs
 
 #endif  // CHROME_BROWSER_PREFS_PROXY_PREFS_H_