Issue 5042 - Adds handling for requests which are not associated with browser tab

lib/requestBlocker.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 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 33 matching lines @@
     devtools.logRequest(
       page, url, type, docDomain,
       thirdParty, sitekey,
       specificOnly, filter
     );
   }
 }
 
 ext.webRequest.onBeforeRequest.addListener((url, type, page, frame) =>
 {
-  if (checkWhitelisted(page, frame))
-    return true;
+  let docDomain = null;
+  let sitekey = null;
 
+  let specificOnly = false;
+  let thirdParty = false;
   let urlString = stringifyURL(url);
-  let docDomain = extractHostFromFrame(frame);
-  let thirdParty = isThirdParty(url, docDomain);
-  let sitekey = getKey(page, frame);
 
-  let specificOnly = !!checkWhitelisted(
-    page, frame, RegExpFilter.typeMap.GENERICBLOCK
+  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 filter = defaultMatcher.matchesAny(
     urlString, RegExpFilter.typeMap[type],
     docDomain, thirdParty, sitekey, specificOnly
   );
 
   setTimeout(onBeforeRequestAsync, 0, page, urlString,
                                       type, docDomain,
                                       thirdParty, sitekey,
                                       specificOnly, filter);
@@ skipping 87 matching lines @@
   if (msg.requestType in chrome.webRequest.ResourceType)
     return false;
 
   return ext.webRequest.onBeforeRequest._dispatch(
      new URL(msg.url),
      msg.requestType,
      sender.page,
      sender.frame
   ).includes(false);
 });