Add a group policy controlling which sites can install extensions.

chrome/browser/policy/configuration_policy_handler_list.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_list.h"
 
 #include "base/stl_util.h"
 #include "base/values.h"
 #include "chrome/browser/policy/configuration_policy_handler.h"
 #include "chrome/browser/policy/policy_error_map.h"
@@ skipping 318 matching lines @@
   handlers_.push_back(new SyncPolicyHandler());
 
   handlers_.push_back(
       new ExtensionListPolicyHandler(key::kExtensionInstallWhitelist,
                                      prefs::kExtensionInstallAllowList,
                                      false));
   handlers_.push_back(
       new ExtensionListPolicyHandler(key::kExtensionInstallBlacklist,
                                      prefs::kExtensionInstallDenyList,
                                      true));
+  handlers_.push_back(
+      new ExtensionURLPatternListPolicyHandler(
+          key::kExtensionInstallSources,
+          prefs::kExtensionAllowedInstallSites));
 
 #if !defined(OS_CHROMEOS)
   handlers_.push_back(new DownloadDirPolicyHandler());
 #endif  // !defined(OS_CHROMEOS)
 
 #if defined(OS_CHROMEOS)
   handlers_.push_back(
       new NetworkConfigurationPolicyHandler(
           key::kDeviceOpenNetworkConfiguration,
           chromeos::NetworkUIData::ONC_SOURCE_DEVICE_POLICY));
@@ skipping 32 matching lines @@
 }
 
 void ConfigurationPolicyHandlerList::PrepareForDisplaying(
     PolicyMap* policies) const {
   std::vector<ConfigurationPolicyHandler*>::const_iterator handler;
   for (handler = handlers_.begin(); handler != handlers_.end(); ++handler)
     (*handler)->PrepareForDisplaying(policies);
 }
 
 }  // namespace policy