Issue 5316 - Adds supported filter types export value to requestBlocker

lib/requestBlocker.js

Index: lib/requestBlocker.js
===================================================================
--- a/lib/requestBlocker.js
+++ b/lib/requestBlocker.js
@@ -48,16 +48,37 @@
   // Treat navigator.sendBeacon() the same as <a ping>, it's essentially the
   // same concept - merely generalized.
   yield ["beacon", "PING"];
 
   // Treat <img srcset> and <picture> the same as other images.
   yield ["imageset", "IMAGE"];
 }());
 
+exports.filterTypes = new Set(function*()
+{
+  // Microsoft Edge does not have webRequest.ResourceType or the devtools panel.
+  // Since filterTypes is only used by devtools, we can just bail out here.
+  if (!(chrome.webRequest.ResourceType))
+    return;
+
+  for (let type in chrome.webRequest.ResourceType)
+    yield resourceTypes.get(chrome.webRequest.ResourceType[type]) || "OTHER";
+
+  // WEBSOCKET and WEBRTC get addressed through workarounds, even if the
+  // webRequest API is lacking support to block these kind of requests.
+  yield "WEBSOCKET";
+  yield "WEBRTC";
+
+  // POPUP and ELEMHIDE filters aren't blocked on the request level but by other
+  // means. They don't have a corresponding value in webRequest.ResourceType.
+  yield "POPUP";
+  yield "ELEMHIDE";
+}());
+
 function onBeforeRequestAsync(page, url, type, docDomain,
                               thirdParty, sitekey,
                               specificOnly, filter)
 {
   if (filter)
     FilterNotifier.emit("filter.hitCount", filter, 0, 0, page);
 
   if (devtools)