Add support for transparent background API

chrome/common/extensions/permissions/chrome_api_permissions.cc

 // Copyright (c) 2013 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/chrome_api_permissions.h"
 
 #include "extensions/common/permissions/api_permission.h"
 #include "extensions/common/permissions/api_permission_set.h"
 #include "extensions/common/permissions/media_galleries_permission.h"
 #include "extensions/common/permissions/permission_message.h"
@@ skipping 346 matching lines @@
         {APIPermission::kSystemNetwork, "system.network"},
         {APIPermission::kSystemDisplay, "system.display"},
         {APIPermission::kSystemStorage, "system.storage"},
         {APIPermission::kPointerLock, "pointerLock"},
         {APIPermission::kFullscreen, "app.window.fullscreen"},
         {APIPermission::kAudio, "audio"},
         {APIPermission::kCastStreaming, "cast.streaming"},
         {APIPermission::kOverrideEscFullscreen,
          "app.window.fullscreen.overrideEsc"},
         {APIPermission::kWindowShape, "app.window.shape"},
+        {APIPermission::kAlphaEnabled, "app.window.alpha"},
         {APIPermission::kBrowser, "browser"},
 
         // Settings override permissions.
         {APIPermission::kHomepage, "homepage",
          APIPermissionInfo::kFlagCannotBeOptional |
              APIPermissionInfo::kFlagInternal,
          IDS_EXTENSION_PROMPT_WARNING_HOME_PAGE_SETTING_OVERRIDE,
          PermissionMessage::kHomepage},
         {APIPermission::kSearchProvider, "searchProvider",
          APIPermissionInfo::kFlagCannotBeOptional |
@@ skipping 32 matching lines @@
       PermissionsProvider::AliasInfo("app.window.fullscreen.overrideEsc",
                                      kOldOverrideEscFullscreenPermission));
   aliases.push_back(PermissionsProvider::AliasInfo(
       "unlimitedStorage", kOldUnlimitedStoragePermission));
   aliases.push_back(PermissionsProvider::AliasInfo(
       "tabs", kWindowsPermission));
   return aliases;
 }
 
 }  // namespace extensions