Issue 6424 - Use internal symbol in ext namespace

lib/requestBlocker.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 73 matching lines @@
   if (devtools)
   {
     devtools.logRequest(
       page, url, type, docDomain,
       thirdParty, sitekey,
       specificOnly, filter
     );
   }
 }
 
-ext.webRequest.onBeforeRequest.addListener((url, type, page, frame) =>
+function shouldAllowRequest(url, type, page, frame)
 {
   let docDomain = null;
   let sitekey = null;
   let specificOnly = false;
   let thirdParty = false;
   let urlString = stringifyURL(url);
 
-
   if (frame && page)
   {
     if (checkWhitelisted(page, frame))
       return true;
 
     docDomain = extractHostFromFrame(frame);
     sitekey = getKey(page, frame);
     thirdParty = isThirdParty(url, docDomain);
     specificOnly = !!checkWhitelisted(page, frame,
                                       RegExpFilter.typeMap.GENERICBLOCK);
   }
 
   let mappedType = resourceTypes.get(type) || "OTHER";
 
   let filter = defaultMatcher.matchesAny(
     urlString, RegExpFilter.typeMap[mappedType],
     docDomain, thirdParty, sitekey, specificOnly
   );
 
   setTimeout(onBeforeRequestAsync, 0, page, urlString,
                                       mappedType, docDomain,
                                       thirdParty, sitekey,
                                       specificOnly, filter);
 
   return !(filter instanceof BlockingFilter);
-});
+}
+
+ext.webRequest.onBeforeRequest.addListener(shouldAllowRequest);
 
 port.on("filters.collapse", (message, sender) =>
 {
   if (checkWhitelisted(sender.page, sender.frame))
     return false;
 
   let typeMask = RegExpFilter.typeMap[message.mediatype];
   let documentHost = extractHostFromFrame(sender.frame);
   let sitekey = getKey(sender.page, sender.frame);
   let blocked = false;
@@ skipping 72 matching lines @@
   // messages from the wrapper here (see https://crbug.com/129353). Hopefully
   // WebRTC will be supported soon too (see https://crbug.com/707683).
   // Edge supports neither webRequest.ResourceType nor WebSocket blocking yet:
   // https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/10297376/
   if (browser.webRequest.ResourceType &&
       (msg.requestType.toUpperCase() in browser.webRequest.ResourceType))
   {
     return false;
   }
 
-  return ext.webRequest.onBeforeRequest._dispatch(
-     new URL(msg.url),
-     msg.requestType,
-     sender.page,
-     sender.frame
-  ).includes(false);
+  return !shouldAllowRequest(new URL(msg.url), msg.requestType, sender.page,
+                             sender.frame);
 });