Cleanup the UseSharedProxies preference.

chrome/browser/chromeos/ui_proxy_config_service.cc

 // Copyright 2013 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.
 
 #include "chrome/browser/chromeos/ui_proxy_config_service.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/values.h"
 #include "chrome/browser/chromeos/net/proxy_config_handler.h"
@@ skipping 38 matching lines @@
 
 // Returns true if proxy settings of |network| are editable.
 bool IsNetworkProxySettingsEditable(const NetworkState& network) {
   onc::ONCSource source = network.onc_source();
   return source != onc::ONC_SOURCE_DEVICE_POLICY &&
       source != onc::ONC_SOURCE_USER_POLICY;
 }
 
 }  // namespace
 
-UIProxyConfigService::UIProxyConfigService() {
+UIProxyConfigService::UIProxyConfigService()
+    : signin_screen_(false),
+      pref_service_(NULL) {
 }
 
 UIProxyConfigService::~UIProxyConfigService() {
 }
 
-void UIProxyConfigService::SetPrefs(PrefService* pref_service) {
+void UIProxyConfigService::SetPrefs(bool signin_screen,
+                                    PrefService* pref_service) {
+  signin_screen_ = signin_screen;
   pref_service_ = pref_service;
 }
 
 void UIProxyConfigService::SetCurrentNetwork(
     const std::string& current_network) {
   const NetworkState* network = NULL;
   if (!current_network.empty()) {
     network = NetworkHandler::Get()->network_state_handler()->GetNetworkState(
         current_network);
     LOG_IF(ERROR, !network)
@@ skipping 74 matching lines @@
   current_ui_config_.FromNetProxyConfig(effective_config);
   current_ui_config_.state = effective_config_state;
   if (ProxyConfigServiceImpl::PrefPrecedes(effective_config_state)) {
     current_ui_config_.user_modifiable = false;
   } else if (!IsNetworkProxySettingsEditable(network)) {
     // TODO(xiyuan): Figure out the right way to set config state for managed
     // network.
     current_ui_config_.state = ProxyPrefs::CONFIG_POLICY;
     current_ui_config_.user_modifiable = false;
   } else {
-    current_ui_config_.user_modifiable =
-        !ProxyConfigServiceImpl::IgnoreProxy(pref_service_,
-                                             network.profile_path(),
-                                             network.onc_source());
+    current_ui_config_.user_modifiable = !ProxyConfigServiceImpl::IgnoreProxy(
+        signin_screen_ ? NULL : pref_service_,
+        network.profile_path(),
+        network.onc_source());
   }
 }
 
 }  // namespace chromeos