function onSnapshotLoaded(tileRect, snapshot)
        {
            this._disposeSnapshot();
            this._lastLoadedSnapshot = snapshot;
            this._imageView.setMask(tileRect);
            if (!snapshot) {
                this._imageView.showImage();
                return;
            }
            snapshot.commandLog(onCommandLogDone.bind(this, snapshot, tileRect));
        }
@param {?DOMAgent.Rect} tileRect
@param {?WebInspector.PaintProfilerSnapshot} snapshot
@this WebInspector.TimelinePaintProfilerView