Add Mozilla's Nielsen shim script

Redirecting the Nielsen script to to Mozilla's shim script[1] instead
of blocking it fixes some websites. Let's do that.

1 - https://searchfox.org/mozilla-central/source/browser/extensions/webcompat/shims/nielsen.js

mapping.json

@@ -53,6 +53,9 @@
     "imasdk.googleapis.com": [
         { "regexRule": "imasdk\\.googleapis\\.com\\/js\\/sdkloader\\/ima3\\.js", "surrogate": "google-ima.js" }
     ],
+    "imrworldwide.com": [
+        { "regexRule": "imrworldwide\\.com\\/v60\\.js", "surrogate": "nielsen.js" }
+    ],
     "npttech.com": [
         { "regexRule": "npttech\\.com\\/advertising\\.js", "surrogate": "noop.js" }
     ],

surrogates/nielsen.js

@@ -0,0 +1,120 @@
+"use strict";
+
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Based on https://searchfox.org/mozilla-central/source/browser/extensions/webcompat/shims/nielsen.js
+
+/* eslint indent: ["error", 2], quotes: ["error", "double"],
+   comma-dangle: ["error", "only-multiline"], space-before-function-paren: ["error", "never"],
+   lines-between-class-members: ["off"] */
+
+/**
+ * Bug 1760754 - Shim Nielsen tracker
+ *
+ * Sites expecting the Nielsen tracker to load properly can break if it
+ * is blocked. This shim mitigates that breakage by loading a stand-in.
+ */
+
+if (!window.nol_t) {
+  const cid = "";
+
+  let domain = "";
+  let schemeHost = "";
+  let scriptName = "";
+  try {
+    const url = document?.currentScript?.src;
+    const { pathname, protocol, host } = new URL(url);
+    domain = host.split(".").slice(0, -2).join(".");
+    schemeHost = `${protocol}//${host}/`;
+    scriptName = pathname.split("/").pop();
+  } catch (_) {}
+
+  class NolTracker {
+    constructor() {
+      this.CONST = {
+        max_tags: 20,
+      };
+      this.feat = {};
+      this.globals = {
+        cid,
+        content: "0",
+        defaultApidFile: "config250",
+        defaultErrorParams: {
+          nol_vcid: "c00",
+          nol_clientid: "",
+        },
+        domain,
+        fpidSfCodeList: [""],
+        init() {},
+        tagCurrRetry: -1,
+        tagMaxRetry: 3,
+        wlCurrRetry: -1,
+        wlMaxRetry: 3,
+      };
+      this.pmap = [];
+      this.pvar = {
+        cid,
+        content: "0",
+        cookies_enabled: "n",
+        server: domain,
+      };
+      this.scriptName = [scriptName];
+      this.version = "6.0.107";
+    }
+    addScript() {}
+    catchLinkOverlay() {}
+    clickEvent() {}
+    clickTrack() {}
+    // eslint-disable-next-line camelcase
+    do_sample() {}
+    downloadEvent() {}
+    eventTrack() {}
+    filter() {}
+    fireToUrl() {}
+    getSchemeHost() {
+      return schemeHost;
+    }
+    getVersion() {}
+    iframe() {}
+    // eslint-disable-next-line camelcase
+    in_sample() {
+      return true;
+    }
+    injectBsdk() {}
+    invite() {}
+    linkTrack() {}
+    mergeFeatures() {}
+    pageEvent() {}
+    pause() {}
+    populateWhitelist() {}
+    post() {}
+    postClickTrack() {}
+    postData() {}
+    postEvent() {}
+    postEventTrack() {}
+    postLinkTrack() {}
+    prefix() {
+      return "";
+    }
+    processDdrsSvc() {}
+    random() {}
+    record() {
+      return this;
+    }
+    regLinkOverlay() {}
+    regListen() {}
+    retrieveCiFileViaCors() {}
+    sectionEvent() {}
+    sendALink() {}
+    sendForm() {}
+    sendIt() {}
+    slideEvent() {}
+    whitelistAssigned() {}
+  };
+
+  window.nol_t = () => {
+    return new NolTracker();
+  };
+}