Take the Extension Storage API out of experimental.

chrome/common/extensions/extension_permission_set.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/common/extensions/extension_permission_set.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/memory/singleton.h"
@@ skipping 237 matching lines @@
       kInputMethodPrivate, "inputMethodPrivate", 0,
       ExtensionPermissionMessage::kNone, kFlagCannotBeOptional, kTypeDefault);
   info->RegisterPermission(
       kManagement, "management", IDS_EXTENSION_PROMPT_WARNING_MANAGEMENT,
       ExtensionPermissionMessage::kManagement, kFlagNone, kTypeDefault);
   info->RegisterPermission(
       kPageCapture, "pageCapture",
       IDS_EXTENSION_PROMPT_WARNING_ALL_PAGES_CONTENT,
       ExtensionPermissionMessage::kAllPageContent, kFlagNone, kTypeDefault);
   info->RegisterPermission(
+      kStorage, "storage", 0,
+      ExtensionPermissionMessage::kNone, kFlagNone, kTypeDefault);
+  info->RegisterPermission(
       kTab, "tabs", IDS_EXTENSION_PROMPT_WARNING_TABS,
       ExtensionPermissionMessage::kTabs, kFlagNone,
       kTypeDefault - kTypePlatformApp);
   info->RegisterPermission(
       kTts, "tts", 0,
       ExtensionPermissionMessage::kNone, kFlagCannotBeOptional, kTypeDefault);
   info->RegisterPermission(
       kTtsEngine, "ttsEngine", IDS_EXTENSION_PROMPT_WARNING_TTS_ENGINE,
       ExtensionPermissionMessage::kTtsEngine,
       kFlagCannotBeOptional, kTypeDefault);
@@ skipping 597 matching lines @@
   std::set<std::string> new_hosts_set(GetDistinctHosts(new_list, false, false));
   std::set<std::string> old_hosts_set(GetDistinctHosts(old_list, false, false));
   std::set<std::string> new_hosts_only;
 
   std::set_difference(new_hosts_set.begin(), new_hosts_set.end(),
                       old_hosts_set.begin(), old_hosts_set.end(),
                       std::inserter(new_hosts_only, new_hosts_only.begin()));
 
   return !new_hosts_only.empty();
 }