Remove ListValue::Append(new {Fundamental,String}Value(...)) pattern in //chrome

chrome/common/extensions/manifest_tests/extension_manifests_validapp_unittest.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 <memory>
 #include <utility>
 
 #include "base/values.h"
 #include "chrome/common/extensions/manifest_handlers/app_launch_info.h"
 #include "chrome/common/extensions/manifest_tests/chrome_manifest_test.h"
@@ skipping 13 matching lines @@
   EXPECT_EQ(GURL("http://www.google.com/mail/"),
             extensions::AppLaunchInfo::GetLaunchWebURL(extension.get()));
 }
 
 TEST_F(ValidAppManifestTest, AllowUnrecognizedPermissions) {
   std::string error;
   std::unique_ptr<base::DictionaryValue> manifest(
       LoadManifest("valid_app.json", &error));
   base::ListValue* permissions = NULL;
   ASSERT_TRUE(manifest->GetList("permissions", &permissions));
-  permissions->Append(new base::StringValue("not-a-valid-permission"));
+  permissions->AppendString("not-a-valid-permission");
   LoadAndExpectSuccess(ManifestData(std::move(manifest), ""));
 }