Create OOBE screen for Voice Interaction value proposition

chrome/browser/resources/chromeos/login/oobe_voice_interaction_value_prop.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 Polymer element for displaying material design voice
+ * interaction value prop screen.
+ */
+
+Polymer({
+  is: 'oobe-voice-interaction-value-prop-md',
+  /**

[xc, 2017/05/31 18:37:52]

nit: newline above

[yueli, 2017/06/02 02:03:47]

Done.

+   * On-tap event handler for no thanks button.
+   *
+   * @private
+   */
+  onNoThanksTap_: function() {
+    chrome.send('login.VoiceInteractionValuePropScreen.userActed',

[xiyuan, 2017/05/30 19:26:22]

Existing polymer elements are firing events to let the hosting screen js to do
the chrome.send. Should we follow that pattern ?

[yueli, 2017/06/02 02:03:47]

Seems the use pattern is mixed -- some polymer elements directly call
chrome.send such as oobe_reset.js and oobe_eula.js

[xiyuan, 2017/06/02 22:12:33]

I would argue that chrome.send and the messages sent are kind of anti polymer
pattern and makes the element not really re-usable.

But I guess we will never reuse it anywhere else. So this is optional and you
can leave as-is.

+        ['no-thanks-pressed']);
+  },
+
+  /**
+   * On-tap event handler for continue button.
+   *
+   * @private
+   */
+  onContinueTap_: function() {
+    chrome.send('login.VoiceInteractionValuePropScreen.userActed',
+        ['continue-pressed']);
+  },
+});