Tune to closure scopes, add comment, rename attachToLayer to

copyRemoteContentToShadowRoot

Author: prushforth

src/mapml/layers/MapMLLayer.js

@@ -1534,9 +1534,7 @@ export var MapMLLayer = L.Layer.extend({
           getExtentLayerControls();
           layer._styles = getAlternateStyles();
           layer._validateExtent();
-          if (this.responseXML) {
-            attachToLayer.call(layer);
-          }
+          copyRemoteContentToShadowRoot();
           // update controls if needed based on mapml-viewer controls/controlslist attribute
           if (layer._layerEl.parentElement) {
             // if layer does not have a parent Element, do not need to set Controls
@@ -1676,9 +1674,14 @@ export var MapMLLayer = L.Layer.extend({
           layer._title = mapml.getAttribute('label').trim();
         }
       }
-      function attachToLayer() {
+      function copyRemoteContentToShadowRoot() {
+        // only run when content is loaded from network, puts features etc
+        // into layer shadow root
+        if (!xhr) {
+          return;
+        }
         let mapml = xhr.responseXML,
-          shadowRoot = this._layerEl.shadowRoot;
+          shadowRoot = layer._layerEl.shadowRoot;
         let elements = mapml.children[0].children[1].children;
         if (elements) {
           let baseURL = mapml.children[0].children[0]
@@ -1781,7 +1784,7 @@ export var MapMLLayer = L.Layer.extend({
     }
   },
   // a layer must share a projection with the map so that all the layers can
-  // be overlayed in one coordinate space.  WGS84 is a 'wildcard', sort of.
+  // be overlayed in one coordinate space.
   getProjection: function () {
     if (!this._extent) {
       return;