function onSnapshotLoaded(paintEvent, rect, snapshot)
        {
            if (!rect || !snapshot)
                return;
            // We're too late and there's a new generation of tiles being loaded.
            if (originalTiles !== this._paintTiles) {
                snapshot.dispose();
                return;
            }
            this._paintTiles.push({layerId: paintEvent.layerId(), rect: rect, snapshot: snapshot, traceEvent: paintEvent.event()});
        }
@param {!WebInspector.LayerPaintEvent} paintEvent
@param {?Array.<number>} rect
@param {?WebInspector.PaintProfilerSnapshot} snapshot
@this {WebInspector.TimelineLayersView}