| Index: tracing/tracing/ui/tracks/slice_group_track.html | 
| diff --git a/tracing/tracing/ui/tracks/slice_group_track.html b/tracing/tracing/ui/tracks/slice_group_track.html | 
| index f8f0f3949f9480b73ab3d90fa91ff9d4339f8b30..bcb4db97e51d872da746e280c06e0a751b42eec0 100644 | 
| --- a/tracing/tracing/ui/tracks/slice_group_track.html | 
| +++ b/tracing/tracing/ui/tracks/slice_group_track.html | 
| @@ -27,7 +27,7 @@ tr.exportTo('tr.ui.tracks', function() { | 
|  | 
| decorate: function(viewport) { | 
| tr.ui.tracks.MultiRowTrack.prototype.decorate.call(this, viewport); | 
| -      this.classList.add('slice-group-track'); | 
| +      Polymer.dom(this).classList.add('slice-group-track'); | 
| this.group_ = undefined; | 
| // Set the collapse threshold so we don't collapse by default, but the | 
| // user can explicitly collapse if they want it. | 
|  |