Bug 1636371 - UrlClassifierSkipListService.jsm should call the observer even when RemoteSettings have not been received yet, r=johannh

Differential Revision: https://phabricator.services.mozilla.com/D73925

netwerk/url-classifier/UrlClassifierSkipListService.jsm

@@ -28,7 +28,7 @@ class Feature {
     }
   }
 
-  async addObserver(observer) {
+  async addAndRunObserver(observer) {
     this.observers.add(observer);
     this.notifyObservers(observer);
   }
@@ -58,19 +58,16 @@ class Feature {
   }
 
   notifyObservers(observer = null) {
-    // Don't notify until we have the initial data.
-    if (!this.remoteEntries) {
-      return;
-    }
-
     let entries = [];
     if (this.prefValue) {
       entries = this.prefValue.split(",");
     }
 
+    if (this.remoteEntries) {
       for (let entry of this.remoteEntries) {
         entries.push(entry);
       }
+    }
 
     let entriesAsString = entries.join(",").toLowerCase();
     if (observer) {
@@ -153,7 +150,7 @@ UrlClassifierSkipListService.prototype = {
         featureObj.onRemoteSettingsUpdate(this.entries);
       }
     }
-    this.features[feature].addObserver(observer);
+    this.features[feature].addAndRunObserver(observer);
   },
 
   unregisterSkipListObserver(feature, observer) {

toolkit/components/url-classifier/tests/unit/test_SkipListService.js

@@ -69,8 +69,10 @@ add_task(async function test_list_changes() {
     obs
   );
 
-  let list = await promise;
+  Assert.equal(await promise, "", "No items in the list");
 
+  // Second event is from the RemoteSettings record.
+  let list = await waitForEvent(updateEvent, "update");
   Assert.equal(list, "example.com", "Has one item in the list");
 
   records.push(
@@ -203,9 +205,10 @@ add_task(async function test_list_init_data() {
   );
 
   let list = await promise;
+  Assert.equal(list, "", "Empty list initially");
 
   Assert.equal(
-    list,
+    await waitForEvent(updateEvent, "update"),
     "tracking.example.com,*.tracking.org",
     "Has several items in the list"
   );