Issue 7334 - Remove support for callbacks in API wrappers

polyfill.js

 /*
  * 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
@@ skipping 94 matching lines @@
     let {object, name, func} = wrappables;
 
     // If the property is not writable assigning it will fail, so we use
     // Object.defineProperty here instead. Assuming the property isn't
     // inherited its other attributes (e.g. enumerable) are preserved,
     // except for accessor attributes (e.g. get and set) which are discarded
     // since we're specifying a value.
     Object.defineProperty(object, name, {
       value(...args)
       {
-        let lastArgumentType = typeof args[args.length - 1];
-
-        // If the last argument is undefined, we assume it stands for the
-        // optional callback.
-        if (lastArgumentType == "function" || lastArgumentType == "undefined")
-          throw new Error("Callbacks are no longer supported.");
-
         let resolvePromise = null;
         let rejectPromise = null;
 
         func.call(object, ...args, result =>
         {
           let error = browser.runtime.lastError;
           if (error && !portClosedBeforeResponseError.test(error.message))
           {
             // runtime.lastError is already an Error instance on Edge, while on
             // Chrome it is a plain object with only a message property.
@@ skipping 224 matching lines @@
 if (typeof OffscreenCanvas == "undefined")
 {
   self.OffscreenCanvas = function(width, height)
   {
     let canvas = document.createElement("canvas");
     canvas.width = width;
     canvas.height = height;
     return canvas;
   };
 }