page.js

// base page that all others extend
// src/scripts/app/views/base/page.js

define([
  "app",
  "views/common/navigation",
  "views/common/searchOverlay",
  "views/common/your-custom-gigya"
], function(app, NavigationView, SearchView, MyGigyaView) {

  return app.views.BaseView.extend({
    // Each page's root view is the body element
    el: document.body,

    // If you overwrite this function be sure to call
    initialize: function() {
        // ... stuff here
        
        // make your stuff work
        MyGigyaView();
    }
  });

});

your-custom-gigya.js

// put this in
// src/scripts/app/views/common/

define([ "app" ], function(app) {
    // if you want something to run the second this file
    // has been downloaded, put it outside of the returned
    //function.
    
    return function() {
        // initialize your custom integration here.
        // app namespace is available for you to use
        // if you so desire.
    }
});