function setUp() {
  // Reset event register.
  firebaseui.auth.EventRegister.map_ = {};
  firebaseui.auth.EventRegister.counter_ = 0;
  // Create DOM element and append to document.
  root = goog.dom.createDom(goog.dom.TagName.DIV);
  document.body.appendChild(root);
  // Create another DOM element and append to document.
  root2 = goog.dom.createDom(goog.dom.TagName.DIV);
  document.body.appendChild(root2);
}
@fileoverview Tests for custom event dispatcher and register.