How to check window before pageMod runs

main.js

var _meta = worker.window.document.querySelector('meta[property="og:site_name"]');
if (worker.window.location.hostname === "bitbucket.org" || (_meta && _meta.attributes.content.value === 'GitHub')) {
  var data = require('sdk/self').data,
   pageMod = require('sdk/page-mod'),
     prefs = require('sdk/simple-prefs').prefs;

  pageMod.PageMod({
    include: '*',
    contentScriptFile : [data.url('jquery-2.1.3.min.js'),
                         data.url('codecov.js')
                        ],
    contentStyleFile  : [data.url('codecov.css')
                        ],
    contentScriptWhen : 'end',
    onAttach: function(worker){
      worker.port.emit('preferences', prefs);
    }
  });
}

Goal is to only mod the page when on Bitbucket, Github and Github Enterprise

We have enterprise customers whom would like to utilize the Add-on preventing me from adding specific domains to the include.

Thanks!