Issue 6539, 6782 - Ignore tabs.executeScript error when frame not found

lib/contentFiltering.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 175 matching lines @@
       matchAboutBlank: true,
       runAt: "document_start"
     })
     .catch(error =>
     {
       // Sometimes a frame is added and removed very quickly, in such cases we
       // simply ignore the error.
       if (error.message == "The frame was removed.")
         return;
 
+      // Sometimes the frame in question is just not found. We don't know why
+      // this is exactly, but we simply ignore the error.
+      if (/^No frame with id \d+ in tab \d+\.$/.test(error.message))
+        return;
+
       throw error;
     });
   }
   catch (error)
   {
     // See the comment in the catch block associated with the call to
     // tabs.insertCSS for why we catch and ignore any errors here.
   }
 }
 
@@ skipping 55 matching lines @@
   updateFrameStyles(sender.page.id, sender.frame.id, message.selectors,
                     message.groupName, message.appendOnly);
 });
 
 fetch(browser.extension.getURL("/snippets.js"), {cache: "no-cache"})
 .then(response => response.ok ? response.text() : "")
 .then(text =>
 {
   snippetsLibrarySource = text;
 });