Issue 5027 - Use updated webRequest API for WebSocket blocking

lib/requestBlocker.js

Index: lib/requestBlocker.js
===================================================================
--- a/lib/requestBlocker.js
+++ b/lib/requestBlocker.js
@@ -147,17 +147,24 @@
 FilterNotifier.on("subscription.removed", onFilterChange);
 FilterNotifier.on("subscription.updated", onFilterChange);
 FilterNotifier.on("subscription.disabled", arg => onFilterChange(arg, true));
 FilterNotifier.on("filter.added", onFilterChange);
 FilterNotifier.on("filter.removed", onFilterChange);
 FilterNotifier.on("filter.disabled", arg => onFilterChange(arg, true));
 FilterNotifier.on("load", onFilterChange);
 
-port.on("request.websocket", (msg, sender) =>
+// Before Chrome 58, the webRequest API didn't intercept WebSocket connections,
+// (see https://crbug.com/129353). Hence we patched the WebSocket object as a
+// workaround. WebSocket connections detected by this workaround are handled
+// below.
+if (!("WEBSOCKET" in chrome.webRequest.ResourceType))
 {
-  return ext.webRequest.onBeforeRequest._dispatch(
-    new URL(msg.url),
-    "WEBSOCKET",
-    sender.page,
-    sender.frame
-  ).indexOf(false) != -1;
-});
+  port.on("request.websocket", (msg, sender) =>
+  {
+    return ext.webRequest.onBeforeRequest._dispatch(
+      new URL(msg.url),
+      "WEBSOCKET",
+      sender.page,
+      sender.frame
+    ).indexOf(false) != -1;
+  });
+}