Add missing trace class to carpet traces

Author: rreusser

src/traces/carpet/plot.js

@@ -42,7 +42,7 @@ function plotOne(gd, plotinfo, cd) {
     var gridLayer = plotinfo.plot.selectAll('.carpetlayer');
     var clipLayer = makeg(fullLayout._defs, 'g', 'clips');
 
-    var axisLayer = makeg(gridLayer, 'g', 'carpet' + trace.uid);
+    var axisLayer = makeg(gridLayer, 'g', 'carpet' + trace.uid).classed('trace', true);
     var minorLayer = makeg(axisLayer, 'g', 'minorlayer');
     var majorLayer = makeg(axisLayer, 'g', 'majorlayer');
     var boundaryLayer = makeg(axisLayer, 'g', 'boundarylayer');

src/traces/contourcarpet/plot.js

@@ -137,6 +137,7 @@ function clipBoundary(plotGroup, carpet) {
 function makeContourGroup(plotinfo, cd, id) {
     var plotgroup = plotinfo.plot.select('.maplayer')
         .selectAll('g.contour.' + id)
+        .classed('trace', true)
         .data(cd);
 
     plotgroup.enter().append('g')