arc: Add splash screen for ARC++ Kiosk startup

chrome/browser/resources/chromeos/login/screen_arc_kiosk_splash.js

+// Copyright 2017 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.
+
+/**
+ * @fileoverview ARC Kiosk install/launch app splash screen implementation.
+ */
+
+login.createScreen('ArcKioskSplashScreen', 'arc-kiosk-splash', function() {
+  return {
+    EXTERNAL_API: [
+      'updateArcKioskMessage',
+    ],
+
+    /** @override */
+    decorate: function() {},
+
+    /**
+     * Event handler that is invoked just before the frame is shown.
+     * @param {string} data Screen init payload.
+     */
+    onBeforeShow: function(data) {
+      this.updateApp(data['appInfo']);
+
+      Oobe.getInstance().headerHidden = true;
+      Oobe.getInstance().solidBackground = true;
+    },
+
+    /**
+     * Event handler that is invoked just before the frame is hidden.
+     */
+    onBeforeHide: function() {},
+
+    /**
+     * Updates the app name and icon.
+     * @param {Object} app Details of app being launched.
+     */
+    updateApp: function(app) {
+      $('arc-splash-header').textContent = app.name;
+      $('arc-splash-header').style.backgroundImage = 'url(' + app.iconURL + ')';
+    },
+
+    /**
+     * Updates the message for the current ARC kiosk state.
+     * @param {string} message Description for current state.
+     */
+    updateArcKioskMessage: function(message) {
+      $('arc-splash-launch-text').textContent = message;
+    }
+  };
+});