Issue 5028 - Use browser namespace

polyfill.js

Index: polyfill.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/polyfill.js
@@ -0,0 +1,33 @@
+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-present eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+"use strict";
+
+// Unlike Firefox and Microsoft Edge, Chrome doesn't have a "browser" object,
+// but provides the extension API through the "chrome" namespace
+// (non-standard).
+if (typeof browser == "undefined")
+  window.browser = chrome;
+
+// Workaround since HTMLCollection, NodeList, StyleSheetList, and CSSRuleList
+// didn't have iterator support before Chrome 51.
+// https://bugs.chromium.org/p/chromium/issues/detail?id=401699
+for (let object of [HTMLCollection, NodeList, StyleSheetList, CSSRuleList])
+{
+  if (!(Symbol.iterator in object.prototype))
+    object.prototype[Symbol.iterator] = Array.prototype[Symbol.iterator];
+}