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 321 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 26 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