[ios] Added cr.isIOS function to use in WebUI pages.

ui/webui/resources/js/cr.js

 // 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.
 
 /**
  * The global object.
  * @type {!Object}
  * @const
  */
 var global = this;
@@ skipping 458 matching lines @@
 
     /** Whether this is on vanilla Linux (not chromeOS). */
     get isLinux() {
       return /Linux/.test(navigator.userAgent);
     },
 
     /** Whether this is on Android. */
     get isAndroid() {
       return /Android/.test(navigator.userAgent);
     }
+
+    /** Whether this is on iOS. */
+    get isIOS() {
+      return navigator.platform === 'iPhone' || navigator.platform === 'iPad';

[dpapad, 2016/07/11 20:45:33]

Can we make these comparisons a bit less fragile as follows?

return /(iPhone|iPad)/.test(navigator.platform);

This will match even if the text is not exactly the same (for example if there
is whitespace after 'iPhone').

[Eugene But (OOO till 7-30), 2016/07/11 21:43:12]

Done.

+    }
   };
 }();