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

ui/webui/resources/js/cr.js

Index: ui/webui/resources/js/cr.js
diff --git a/ui/webui/resources/js/cr.js b/ui/webui/resources/js/cr.js
index 090cfd94f7d7067fbfeca0ed4e0a44c97294d7a9..cb1726bcddf13c65d6eca1de7b190e7495628c75 100644
--- a/ui/webui/resources/js/cr.js
+++ b/ui/webui/resources/js/cr.js
@@ -476,5 +476,10 @@ var cr = cr || function() {
     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.

+    }
   };
 }();