Issue 2816 - Restore Preview functionality

chrome/content/composer.js

Index: chrome/content/composer.js
===================================================================
--- a/chrome/content/composer.js
+++ b/chrome/content/composer.js
@@ -3,22 +3,22 @@
  * version 2.0 (the "License"). You can obtain a copy of the License at
  * http://mozilla.org/MPL/2.0/.
  */
 
 let {Prefs} = require("prefs");
 
 let domainData;
 let nodeData;
+let nodeID;
 let selectedNode = null;
 let advancedMode = false;
 let treeView = null;
 let stylesheetData;
 let previewStyle = null;
-let doc;
 
 let abpURL = Cc["@adblockplus.org/abp/public;1"].getService(Ci.nsIURI);
 Cu.import(abpURL.spec);
 
 /*******************
  * TreeView object *
  *******************/
 
@@ -79,18 +79,18 @@ function TreeView_getCellProperties(row,
 }
 
 /*********************
  * General functions *
  *********************/
 
 function init()
 {
-  nodeData = window.arguments[0];
-  let host = window.arguments[1];
+  let host;
+  ({host, nodeData, nodeID} = window.arguments[0]);
 
   // Check whether element hiding group is disabled
   let subscription = AdblockPlus.getSubscription("~eh~");
   if (subscription && subscription.disabled)
   {
     let warning = document.getElementById("groupDisabledWarning");
     if (/\?1\?/.test(warning.textContent))
       warning.textContent = warning.textContent.replace(/\?1\?/g, subscription.title);
@@ -306,18 +306,18 @@ function updateExpression()
   expression = domainData.selected + "##" + expression;
 
   document.getElementById("expression").value = expression;
 
   var tree = document.getElementById("nodes-tree");
   if (tree.view && tree.view.selection)
     tree.treeBoxObject.invalidateRow(tree.view.selection.currentIndex);
 
-  if (previewStyle)
-    previewStyle.textContent = stylesheetData;
+  if (document.getElementById("preview").checked)
+    togglePreview(true);
 }
 
 function escapeChar(dummy, match)
 {
   return "\\" + match.charCodeAt(0).toString(16) + " ";
 }
 
 function fillDomains(domainData) {
@@ -486,39 +486,23 @@ function fillAttributes(nodeData)
   if (advancedMode)
   {
     // Add custom CSS entry
     node = createAttribute("advanced", nodeData.customCSS, list.getAttribute("_labelcustom"), nodeData.customCSS.selected);
     list.appendChild(node);
   }
 }
 
-function togglePreview(preview) {
-  if (preview) {
-    if (!previewStyle || !previewStyle.parentNode) {
-      previewStyle = doc.createElementNS("http://www.w3.org/1999/xhtml", "style");
-      previewStyle.setAttribute("type", "text/css");
-      doc.documentElement.appendChild(previewStyle);
-    }
-    previewStyle.textContent = stylesheetData;
-  }
-  else {
-    try
-    {
-      if (previewStyle && previewStyle.parentNode)
-        previewStyle.parentNode.removeChild(previewStyle);
-    }
-    catch (e)
-    {
-      // if the window was closed (reloaded) we end up with dead object reference
-      // https://bugzilla.mozilla.org/show_bug.cgi?id=695480
-      // just ignore this case
-    }
-    previewStyle = null;
-  }
+function togglePreview(preview, forgetNode)
+{
+  Services.mm.broadcastAsyncMessage("ElemHideHelper:Preview", {
+    nodeID: nodeID,
+    stylesheetData: preview ? stylesheetData : null,
+    forgetNode: !!forgetNode
+  });
 }
 
 function changeDomain(node) {
   domainData.selected = node.getAttribute("value");
   updateExpression();
 }
 
 function toggleAttr(node) {