message <span class="message">ReadyStateChange</span>
{
  enum State
  {
    <span class="comment">/** 
     * Occurs immediately after the DOM environment is created
     * for a document.
     */</span>
    DOM_ENVIRONMENT_CREATED = 1;
    <span class="comment">/** 
     * This state indicates that the HTML tree is done (for now). The event
     * happens immediately after the DOMContentLoaded event fires on the window 
     * object. Useful for figuring out when we can inspect the DOM.
     */</span>
    DOM_CONTENT_LOADED = 2;
    <span class="comment">/** 
     * Occurs after onload is finished, and after external resources are loaded. 
     * When this event is observed, it should be safe to take a screenshot.
     */</span>
    AFTER_ONLOAD = 3;
  }

  required <span class="number">uint32</span> runtimeID = 1; 
  required <span class="number">State </span> state     = 2; 
}
