Cache --whitelisted-extension-id in SimpleFeature.

chrome/common/extensions/manifest_tests/extension_manifests_launcher_page_unittest.cc

 // Copyright 2014 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 "base/command_line.h"
 #include "chrome/common/extensions/manifest_tests/chrome_manifest_test.h"
 #include "extensions/common/constants.h"
 #include "extensions/common/extension.h"
+#include "extensions/common/features/simple_feature.h"
 #include "extensions/common/manifest_handlers/launcher_page_info.h"
 #include "extensions/common/switches.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace extensions {
 
 namespace {
 
 // The ID of test manifests requiring whitelisting.
 const char kWhitelistID[] = "lmadimbbgapmngbiclpjjngmdickadpl";
 
 }  // namespace
 
 typedef ChromeManifestTest LauncherPageManifestTest;
 
 TEST_F(LauncherPageManifestTest, ValidLauncherPage) {
-  base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
-      extensions::switches::kWhitelistedExtensionID, kWhitelistID);
+  extensions::SimpleFeature::ScopedWhitelistForTest whitelist(kWhitelistID);
   scoped_refptr<extensions::Extension> extension(
       LoadAndExpectSuccess("init_valid_launcher_page.json"));
   ASSERT_TRUE(extension.get());
   extensions::LauncherPageInfo* info =
       extensions::LauncherPageHandler::GetInfo(extension.get());
   ASSERT_TRUE(info);
   EXPECT_EQ("test.html", info->page);
 }
 
 }  // namespace extensions