Highlighting now works with the web worker

src/core/ChefWorker.js

@@ -53,6 +53,13 @@ self.addEventListener("message", function(e) {
             // imported into an inline worker.
             self.docURL = e.data.data;
             break;
+        case "highlight":
+            calculateHighlights(
+                e.data.data.recipeConfig,
+                e.data.data.direction,
+                e.data.data.pos
+            );
+            break;
         default:
             break;
     }
@@ -121,6 +128,25 @@ function loadRequiredModules(recipeConfig) {
 }
 
 
+/**
+ * Calculates highlight offsets if possible.
+ *
+ * @param {Object[]} recipeConfig
+ * @param {string} direction
+ * @param {Object} pos - The position object for the highlight.
+ * @param {number} pos.start - The start offset.
+ * @param {number} pos.end - The end offset.
+ */
+function calculateHighlights(recipeConfig, direction, pos) {
+    pos = self.chef.calculateHighlights(recipeConfig, direction, pos);
+
+    self.postMessage({
+        action: "highlightsCalculated",
+        data: pos
+    });
+}
+
+
 /**
  * Send status update to the app.
  *