Fix hiding behavior when creating app windows.

chrome/test/data/extensions/platform_apps/hidden_with_id/test.js

+// Copyright 2015 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.
+
+function sendLaunchedAndRunReply() {
+  chrome.test.sendMessage('Launched', function (reply) {
+    if (reply)
+      window[reply]();
+  });
+}
+
+function createHidden() {
+  chrome.app.window.create('empty.html', {
+    id: 'hidden_with_id',
+    hidden: true,
+  }, function () {
+    sendLaunchedAndRunReply();
+  });
+}
+
+function createVisible() {
+  chrome.app.window.create('empty.html', {
+    id: 'hidden_with_id',
+  }, function () {
+    sendLaunchedAndRunReply();
+  });
+}
+
+chrome.app.runtime.onLaunched.addListener(function() {
+  sendLaunchedAndRunReply();
+});