arc: Add Goolge Privacy Policy link to OptIn UI.

chrome/browser/resources/chromeos/arc_support/playstore.js

 // Copyright 2016 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.
 
 /**
  * Processes select tag that contains list of available terms for different
  * languages and zones. In case of initial load, tries to find terms that match
  * exactly current language and country code and automatically redirects the
  * view in case such terms are found. Leaves terms in select tag that only match
  * current language or country code or default English variant or currently
@@ skipping 94 matching lines @@
   // Remove header element that contains logo image we don't want to show in
   // our view.
   var doc = document;
   document.body.removeChild(doc.getElementById('play-header'));
 
   // Hide content at this point. We might want to redirect our view to terms
   // that exactly match current language and country code.
   document.body.hidden = true;
 }
 
+/**
+ * Searches in footer for a privacy policy link.
+ * @return {string} Link to Google Privacy Policy detected from the current
+ *                  document or link to the default policy if it is not found.
+ */
+function getPrivacyPolicyLink() {
+  var doc = document;
+  var links = doc.getElementById('play-footer').getElementsByTagName('a');
+  for (var i = 0; i < links.length; ++i) {
+    var targetURL = links[i].href;
+    if (targetURL.endsWith('/policies/privacy/')) {
+      return targetURL;
+    }
+  }
+  return 'https://www.google.com/policies/privacy/';
+}
+
 formatDocument();
 processLangZoneTerms();