Add a group policy controlling which sites can install extensions.

chrome/browser/extensions/extension_prefs.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/extensions/extension_prefs.h"
 
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/extensions/admin_policy.h"
@@ skipping 1886 matching lines @@
   ExtensionIdSet extension_ids;
   GetExtensions(&extension_ids);
   for (ExtensionIdSet::iterator ext_id = extension_ids.begin();
        ext_id != extension_ids.end(); ++ext_id) {
     content_settings_store_->ClearContentSettingsForExtension(
         *ext_id,
         kExtensionPrefsScopeIncognitoSessionOnly);
   }
 }
 
+URLPatternSet ExtensionPrefs::GetAllowedInstallSites() {
+  URLPatternSet result;
+  const ListValue* list = prefs_->GetList(prefs::kExtensionAllowedInstallSites);
+  if (!list)

[Mattias Nissler (ping if slow), 2012/06/08 09:38:22]

This NULL check is not necessary as pref service will always give you a value.
If the pref is missing, we'll trigger the NOTREACHED() inside PrefService and
crashing is the correct course of action.

+    return result;
+
+  for (size_t i = 0; i < list->GetSize(); ++i) {
+    std::string entry_string;
+    URLPattern entry(URLPattern::SCHEME_ALL);
+    if (!list->GetString(i, &entry_string) ||
+        entry.Parse(entry_string) != URLPattern::PARSE_SUCCESS) {
+      LOG(ERROR) << "Invalid value for preference: "
+                 << prefs::kExtensionAllowedInstallSites
+                 << "." << i;
+      continue;
+    }
+    result.AddPattern(entry);
+  }
+
+  return result;
+}
+
 // static
 void ExtensionPrefs::RegisterUserPrefs(PrefService* prefs) {
   prefs->RegisterDictionaryPref(kExtensionsPref, PrefService::UNSYNCABLE_PREF);
   prefs->RegisterListPref(kExtensionToolbar, PrefService::UNSYNCABLE_PREF);
   prefs->RegisterIntegerPref(prefs::kExtensionToolbarSize,
                              -1,  // default value
                              PrefService::UNSYNCABLE_PREF);
   prefs->RegisterDictionaryPref(kExtensionsBlacklistUpdate,
                                 PrefService::UNSYNCABLE_PREF);
   prefs->RegisterListPref(prefs::kExtensionInstallAllowList,
                           PrefService::UNSYNCABLE_PREF);
   prefs->RegisterListPref(prefs::kExtensionInstallDenyList,
                           PrefService::UNSYNCABLE_PREF);
   prefs->RegisterListPref(prefs::kExtensionInstallForceList,
                           PrefService::UNSYNCABLE_PREF);
   prefs->RegisterStringPref(kWebStoreLogin,
                             std::string(),  // default value
                             PrefService::UNSYNCABLE_PREF);
   prefs->RegisterStringPref(prefs::kExtensionBlacklistUpdateVersion,
                             "0",  // default value
                             PrefService::UNSYNCABLE_PREF);
   prefs->RegisterInt64Pref(prefs::kLastExtensionsUpdateCheck,
                            0,  // default value
                            PrefService::UNSYNCABLE_PREF);
   prefs->RegisterInt64Pref(prefs::kNextExtensionsUpdateCheck,
                            0,  // default value
                            PrefService::UNSYNCABLE_PREF);
+  prefs->RegisterListPref(prefs::kExtensionAllowedInstallSites,
+                          PrefService::UNSYNCABLE_PREF);
 }