Set prefs::kDefaultSearchProviderEnabled to false according to policy.

chrome/browser/policy/configuration_policy_handler.cc

 // Copyright (c) 2012 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/policy/configuration_policy_handler.h"
 
 #include <string>
 
 #include "base/file_path.h"
 #include "base/json/json_writer.h"
@@ skipping 496 matching lines @@
     errors->AddError(key::kDefaultSearchProviderSearchURL,
                      IDS_POLICY_INVALID_SEARCH_URL_ERROR);
     return false;
   }
   return true;
 }
 
 void DefaultSearchPolicyHandler::ApplyPolicySettings(const PolicyMap& policies,
                                                      PrefValueMap* prefs) {
   if (DefaultSearchProviderIsDisabled(policies)) {
+    prefs->SetBoolean(prefs::kDefaultSearchProviderEnabled, false);
+
     // If default search is disabled, the other fields are ignored.
     prefs->SetString(prefs::kDefaultSearchProviderName, std::string());
     prefs->SetString(prefs::kDefaultSearchProviderSearchURL, std::string());
     prefs->SetString(prefs::kDefaultSearchProviderSuggestURL, std::string());
     prefs->SetString(prefs::kDefaultSearchProviderIconURL, std::string());
     prefs->SetString(prefs::kDefaultSearchProviderEncodings, std::string());
     prefs->SetString(prefs::kDefaultSearchProviderKeyword, std::string());
     prefs->SetString(prefs::kDefaultSearchProviderInstantURL, std::string());
     return;
   }
@@ skipping 434 matching lines @@
     }
   }
 
   if (setting != CONTENT_SETTING_DEFAULT) {
     prefs->SetValue(prefs::kManagedDefaultJavaScriptSetting,
                     Value::CreateIntegerValue(setting));
   }
 }
 
 }  // namespace policy