lib/third_party/tracing/model/event_set.js
function(event) {
      if (event.guid == undefined)
        throw new Error('Event must have a GUID');

      if (this.contains(event))
        return event;

      this.pushed_guids_[event.guid] = true;
      this[this.length_++] = event;
      this.bounds_dirty_ = true;
      return event;
    }
function(event) {
      if (event.guid == undefined)
        throw new Error('Event must have a GUID');

      if (this.contains(event))
        return event;

      this.pushed_guids_[event.guid] = true;
      this[this.length_++] = event;
      this.bounds_dirty_ = true;
      return event;
    }
function ( event ) { if ( event . guid == undefined ) throw new Error ( 'Event must have a GUID' ) ; if ( this . contains ( event ) ) return event ; this . pushed_guids_ [ event . guid ] = true ; this [ this . length_ ++ ] = event ; this . bounds_dirty_ = true ; return event ; }
push pushes only unique events. If an event has been already pushed, do nothing.
push pushes only unique events . If an event has been already pushed do nothing .