Issue 5027 - Use updated webRequest API for WebSocket blocking

include.preload.js

Index: include.preload.js
===================================================================
--- a/include.preload.js
+++ b/include.preload.js
@@ -337,20 +337,20 @@
   let script = document.createElement("script");
   script.type = "application/javascript";
   script.async = false;
   script.textContent = "(" + fn + ")(" + JSON.stringify(arg) + ");";
   document.documentElement.appendChild(script);
   document.documentElement.removeChild(script);
 }
 
-// Chrome doesn't allow us to intercept WebSockets[1], and therefore
-// some ad networks are misusing them as a way to serve adverts and circumvent
-// us. As a workaround we wrap WebSocket, preventing blocked WebSocket
-// connections from being opened.
+// Before Chrome 58 the webRequest API didn't allow us to intercept
+// WebSockets[1], and therefore some ad networks are misusing them as a way to
+// serve adverts and circumvent us. As a workaround we wrap WebSocket,
+// preventing blocked WebSocket connections from being opened.
 // [1] - https://bugs.chromium.org/p/chromium/issues/detail?id=129353
 function wrapWebSocket()
 {
   let eventName = "abpws-" + Math.random().toString(36).substr(2);
 
   document.addEventListener(eventName, event =>
   {
     ext.backgroundPage.sendMessage({