Only add from.data: layout if needed. Fixes #992
Only add from.data: layout if needed. Fixes #992
vega/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite