Remove background_alias_do_not_use_permission

chrome/common/extensions/permissions/api_permission.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/permissions/api_permission.h"
 
 #include "chrome/common/extensions/permissions/permissions_info.h"
 #include "grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
 
 namespace {
 
 const char kOldUnlimitedStoragePermission[] = "unlimited_storage";
 const char kWindowsPermission[] = "windows";
-const char kTemporaryBackgroundAlias[] = "background_alias_do_not_use";
 
 }  // namespace
 
 namespace extensions {
 
 //
 // APIPermission
 //
 
 APIPermission::~APIPermission() {}
@@ skipping 154 matching lines @@
     const PermissionRegistration& pr = PermissionsToRegister[i];
     info->RegisterPermission(
         pr.id, pr.name, pr.l10n_message_id,
         pr.message_id ? pr.message_id : PermissionMessage::kNone,
         pr.flags);
   }
 
   // Register aliases.
   info->RegisterAlias("unlimitedStorage", kOldUnlimitedStoragePermission);
   info->RegisterAlias("tabs", kWindowsPermission);
-  // TODO(mihaip): Should be removed for the M20 branch, see
-  // http://crbug.com/120447 for more details.
-  info->RegisterAlias("background", kTemporaryBackgroundAlias);
 }
 
 }  // namespace extensions