Provides a cross-browser safe way to use the Navigation Timing API.
Ported from Bazaarvoice internal code and based on a Paul Irish polyfill.
var perfNow = require('performance/now.js');
var timing = perfNow.now();This is not a true polyfill in browsers that do not implement the Navigation
Timing API. Rather than returning the time elapsed since navigationStart, it
will return the time elapsed since the polyfill was installed.
Also ported from Bazaarvoice internal code.
var perfMark = require('performance/mark.js');
perfMark.mark('mark-name');