Mitigate race conditions on startup.

src/bg/deferWebTraffic.js

@@ -46,6 +46,7 @@ function deferWebTraffic(promiseToWaitFor, next) {
 
    async function waitFor(request) {
     let {type, documentUrl, url, tabId, frameId} = request;
+    debug("deferWebTraffic probing",request);
     if (tabId === browser.tabs.TAB_ID_NONE) return;
     if (!seenTabs.has(tabId)) {
       if (type === "main_frame") {

src/bg/main.js

@@ -204,8 +204,7 @@
 
     async fetchChildPolicy({url, contextUrl}, sender) {
       await ns.initializing;
-      return (messageHandler.fetchChildPolicy =
-        ns.computeChildPolicy)(...arguments);
+      return ns.computeChildPolicy(...arguments);
     },
 
     async openStandalonePopup(tab) {
@@ -416,6 +415,7 @@
     },
 
     async collectSeen(tabId) {
+      await this.initializing;
       try {
         let seen = Array.from(await Messages.send("collect", {uuid: ns.local.uuid}, {tabId, frameId: 0}));
         debug("Collected seen", seen); // DEV_ONLY

src/nscl

@@ -1 +1 @@
-Subproject commit 593c414c9ae7ede326109d5af10e6ff21c4a1138
+Subproject commit 1a94f457568d2708e5e61c6322bfa4f1e50a20ec