Bug 1639969 - explicitly wait the storage permission before cleaning up in test 'browser_storageAccessWithHeuristics.js'. r=baku

Our ETP backend adds the storage permission asynchronously when adding
storage access. So, we have to wait the permission is ready in the
parent process before cleaning up. Otherwise, we will have a incorrect
state after the test.

Differential Revision: https://phabricator.services.mozilla.com/D76372

toolkit/components/antitracking/test/browser/browser_storageAccessWithHeuristics.js

@@ -1,5 +1,22 @@
 /* import-globals-from antitracking_head.js */
 
+function waitStoragePermission() {
+  return new Promise(resolve => {
+    let id = setInterval(async _ => {
+      if (
+        await SpecialPowers.testPermission(
+          `3rdPartyStorage^${TEST_3RD_PARTY_DOMAIN.slice(0, -1)}`,
+          SpecialPowers.Services.perms.ALLOW_ACTION,
+          TEST_DOMAIN
+        )
+      ) {
+        clearInterval(id);
+        resolve();
+      }
+    }, 0);
+  });
+}
+
 add_task(async function() {
   info("Starting subResources test");
 
@@ -413,6 +430,9 @@ add_task(async function testUserInteractionHeuristic() {
 });
 
 add_task(async function() {
+  info("Wait until the storage permission is ready before cleaning up.");
+  await waitStoragePermission();
+
   info("Cleaning up.");
   await new Promise(resolve => {
     Services.clearData.deleteData(Ci.nsIClearDataService.CLEAR_ALL, value =>
@@ -655,6 +675,9 @@ add_task(async function testDoublyNestedUserInteractionHeuristic() {
 });
 
 add_task(async function() {
+  info("Wait until the storage permission is ready before cleaning up.");
+  await waitStoragePermission();
+
   info("Cleaning up.");
   await new Promise(resolve => {
     Services.clearData.deleteData(Ci.nsIClearDataService.CLEAR_ALL, value =>