Issue 2816 - Restore Preview functionality

lib/aardvark.js

 /*
  * This Source Code is subject to the terms of the Mozilla Public License
  * version 2.0 (the "License"). You can obtain a copy of the License at
  * http://mozilla.org/MPL/2.0/.
  */
 
 let {Prefs} = require("prefs");
 
 // Make sure to stop selection when we are uninstalled
 onShutdown.add(() => Aardvark.quit());
@@ skipping 559 matching lines @@
   select: function(elem)
   {
     if (!elem)
       return false;
 
     this.browser.selectedBrowser.messageManager.sendAsyncMessage(
       "ElemHideHelper:GetNodeInfo",
       null,
       {
         element: elem,
-        callback: (nodeData, host) =>
+        callback: (response) =>
         {
+          response = JSON.parse(response);
+          if (!response.nodeData)
+            return;
+
           this.window.openDialog("chrome://elemhidehelper/content/composer.xul",
-              "_blank", "chrome,centerscreen,resizable,dialog=no", nodeData,
-              host);
+              "_blank", "chrome,centerscreen,resizable,dialog=no", response);
           this.quit();
         }
       }
     );
     return false;
   },
 
   blinkElement: function(elem)
   {
     if (!elem)
@@ skipping 163 matching lines @@
     // Show help box
     helpBox.showPopup(this.browser, -1, -1, "tooltip", "topleft", "topleft");
     return true;
   }
 }
 
 // Makes sure event handlers like Aardvark.onKeyPress always have the correct
 // this pointer set.
 for (let method of ["onMouseClick", "onMouseScroll", "onKeyPress", "onPageHide", "onMouseMove", "onAfterPaint", "quit"])
   Aardvark[method] = Aardvark[method].bind(Aardvark);