addAllEventsListener(listener) {
    let id = this.nextListenerId_++;
    this.allEventsListeners_.set(id, listener);
    return id;
  }
/**
   * Listens for all DevTools protocol events and issues the
   * callback upon reception.
   *
   * @param {!chromium.DevTools.Connection.AllEventsFunction} listener The
   *     callback issued when we receive a DevTools protocol event.
   * @return {number} The id of this event listener.
   */
Listens for all DevTools protocol events and issues the
callback upon reception.

@param {!chromium.DevTools.Connection.AllEventsFunction} listener The
callback issued when we receive a DevTools protocol event.
@return {number} The id of this event listener.
Listens for all DevTools protocol events and issues the callback upon reception . @param { !chromium . DevTools . Connection . AllEventsFunction } listener The callback issued when we receive a DevTools protocol event . @return { number } The id of this event listener .
addAllEventsListener(listener) {
    let id = this.nextListenerId_++;
    this.allEventsListeners_.set(id, listener);
    return id;
  }
addAllEventsListener ( listener ) { let id = this . nextListenerId_ ++ ; this . allEventsListeners_ . set ( id , listener ) ; return id ; }
Listens for all DevTools protocol events and issues the
 callback upon reception.
Listens for all DevTools protocol events and issues the callback upon reception .