Bug 1635524 - Part 2: Pass oldSubscription for pushsubscriptionchange event r=asuth

Differential Revision: https://phabricator.services.mozilla.com/D234713

dom/interfaces/base/nsIServiceWorkerManager.idl

@@ -12,6 +12,7 @@ interface mozIDOMWindowProxy;
 interface nsIArray;
 interface nsIInterceptedChannel;
 interface nsIPrincipal;
+interface nsIPushSubscription;
 interface nsIRunnable;
 interface nsIURI;
 %{C++
@@ -320,7 +321,8 @@ interface nsIServiceWorkerManager : nsISupports
                                      in ACString aScope,
                                      [optional] in Array<uint8_t> aDataBytes);
   void sendPushSubscriptionChangeEvent(in ACString aOriginAttributes,
-                                       in ACString scope);
+                                       in ACString scope,
+                                       [optional] in nsIPushSubscription aOldSubscription);
 
   void addListener(in nsIServiceWorkerManagerListener aListener);
 

dom/interfaces/push/nsIPushNotifier.idl

@@ -13,6 +13,7 @@
 %}
 
 interface nsIPrincipal;
+interface nsIPushSubscription;
 
 /**
  * Fires XPCOM observer notifications and service worker events for
@@ -43,7 +44,8 @@ interface nsIPushNotifier : nsISupports
    * `pushsubscriptionchange` event to the service worker registered for the
    * |scope|.
    */
-  void notifySubscriptionChange(in ACString scope, in nsIPrincipal principal);
+  void notifySubscriptionChange(in ACString scope, in nsIPrincipal principal,
+                                [optional] in nsIPushSubscription oldSubscription);
 
   /**
    * Fires a `push-subscription-modified` observer notification. Chrome code

dom/push/ChromePushSubscription.sys.mjs

@@ -0,0 +1,93 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/** `ChromePushSubscription` instances are passed to all subscription callbacks. */
+export class ChromePushSubscription {
+  #props;
+
+  constructor(props) {
+    this.#props = props;
+  }
+
+  QueryInterface = ChromeUtils.generateQI(["nsIPushSubscription"]);
+
+  /** The URL for sending messages to this subscription. */
+  get endpoint() {
+    return this.#props.endpoint;
+  }
+
+  /** The last time a message was sent to this subscription. */
+  get lastPush() {
+    return this.#props.lastPush;
+  }
+
+  /** The total number of messages sent to this subscription. */
+  get pushCount() {
+    return this.#props.pushCount;
+  }
+
+  /** The number of remaining background messages that can be sent to this
+   * subscription, or -1 of the subscription is exempt from the quota.
+   */
+  get quota() {
+    return this.#props.quota;
+  }
+
+  /**
+   * Indicates whether this subscription was created with the system principal.
+   * System subscriptions are exempt from the background message quota and
+   * permission checks.
+   */
+  get isSystemSubscription() {
+    return !!this.#props.systemRecord;
+  }
+
+  /** The private key used to decrypt incoming push messages, in JWK format */
+  get p256dhPrivateKey() {
+    return this.#props.p256dhPrivateKey;
+  }
+
+  /**
+   * Indicates whether this subscription is subject to the background message
+   * quota.
+   */
+  quotaApplies() {
+    return this.quota >= 0;
+  }
+
+  /**
+   * Indicates whether this subscription exceeded the background message quota,
+   * or the user revoked the notification permission. The caller must request a
+   * new subscription to continue receiving push messages.
+   */
+  isExpired() {
+    return this.quota === 0;
+  }
+
+  /**
+   * Returns a key for encrypting messages sent to this subscription. JS
+   * callers receive the key buffer as a return value, while C++ callers
+   * receive the key size and buffer as out parameters.
+   */
+  getKey(name) {
+    switch (name) {
+      case "p256dh":
+        return this.#getRawKey(this.#props.p256dhKey);
+
+      case "auth":
+        return this.#getRawKey(this.#props.authenticationSecret);
+
+      case "appServer":
+        return this.#getRawKey(this.#props.appServerKey);
+    }
+    return [];
+  }
+
+  #getRawKey(key) {
+    if (!key) {
+      return [];
+    }
+    return new Uint8Array(key);
+  }
+}

dom/push/PushComponents.sys.mjs

@@ -8,6 +8,7 @@
  */
 
 import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+import { ChromePushSubscription } from "./ChromePushSubscription.sys.mjs";
 
 var isParent =
   Services.appinfo.processType === Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT;
@@ -488,96 +489,6 @@ Object.assign(PushServiceContent.prototype, {
   },
 });
 
-/** `ChromePushSubscription` instances are passed to all subscription callbacks. */
-class ChromePushSubscription {
-  #props;
-
-  constructor(props) {
-    this.#props = props;
-  }
-
-  QueryInterface = ChromeUtils.generateQI(["nsIPushSubscription"]);
-
-  /** The URL for sending messages to this subscription. */
-  get endpoint() {
-    return this.#props.endpoint;
-  }
-
-  /** The last time a message was sent to this subscription. */
-  get lastPush() {
-    return this.#props.lastPush;
-  }
-
-  /** The total number of messages sent to this subscription. */
-  get pushCount() {
-    return this.#props.pushCount;
-  }
-
-  /** The number of remaining background messages that can be sent to this
-   * subscription, or -1 of the subscription is exempt from the quota.
-   */
-  get quota() {
-    return this.#props.quota;
-  }
-
-  /**
-   * Indicates whether this subscription was created with the system principal.
-   * System subscriptions are exempt from the background message quota and
-   * permission checks.
-   */
-  get isSystemSubscription() {
-    return !!this.#props.systemRecord;
-  }
-
-  /** The private key used to decrypt incoming push messages, in JWK format */
-  get p256dhPrivateKey() {
-    return this.#props.p256dhPrivateKey;
-  }
-
-  /**
-   * Indicates whether this subscription is subject to the background message
-   * quota.
-   */
-  quotaApplies() {
-    return this.quota >= 0;
-  }
-
-  /**
-   * Indicates whether this subscription exceeded the background message quota,
-   * or the user revoked the notification permission. The caller must request a
-   * new subscription to continue receiving push messages.
-   */
-  isExpired() {
-    return this.quota === 0;
-  }
-
-  /**
-   * Returns a key for encrypting messages sent to this subscription. JS
-   * callers receive the key buffer as a return value, while C++ callers
-   * receive the key size and buffer as out parameters.
-   */
-  getKey(name) {
-    switch (name) {
-      case "p256dh":
-        return this.#getRawKey(this.#props.p256dhKey);
-
-      case "auth":
-        return this.#getRawKey(this.#props.authenticationSecret);
-
-      case "appServer":
-        return this.#getRawKey(this.#props.appServerKey);
-    }
-    return [];
-  }
-
-  #getRawKey(key) {
-    if (!key) {
-      return [];
-    }
-    return new Uint8Array(key);
-  }
-}
-
 // Export the correct implementation depending on whether we're running in
 // the parent or content process.
 export let Service = isParent ? PushServiceParent : PushServiceContent;

dom/push/PushManager.cpp

@@ -33,34 +33,6 @@
 
 namespace mozilla::dom {
 
-namespace {
-
-nsresult GetPermissionState(nsIPrincipal* aPrincipal, PermissionState& aState) {
-  nsCOMPtr<nsIPermissionManager> permManager =
-      mozilla::components::PermissionManager::Service();
-
-  if (!permManager) {
-    return NS_ERROR_FAILURE;
-  }
-  uint32_t permission = nsIPermissionManager::UNKNOWN_ACTION;
-  nsresult rv = permManager->TestExactPermissionFromPrincipal(
-      aPrincipal, "desktop-notification"_ns, &permission);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return rv;
-  }
-
-  if (permission == nsIPermissionManager::ALLOW_ACTION ||
-      Preferences::GetBool("dom.push.testing.ignorePermission", false)) {
-    aState = PermissionState::Granted;
-  } else if (permission == nsIPermissionManager::DENY_ACTION) {
-    aState = PermissionState::Denied;
-  } else {
-    aState = PermissionState::Prompt;
-  }
-
-  return NS_OK;
-}
-
 nsresult GetSubscriptionParams(nsIPushSubscription* aSubscription,
                                nsAString& aEndpoint,
                                nsTArray<uint8_t>& aRawP256dhKey,
@@ -91,6 +63,34 @@ nsresult GetSubscriptionParams(nsIPushSubscription* aSubscription,
   return NS_OK;
 }
 
+namespace {
+
+nsresult GetPermissionState(nsIPrincipal* aPrincipal, PermissionState& aState) {
+  nsCOMPtr<nsIPermissionManager> permManager =
+      mozilla::components::PermissionManager::Service();
+
+  if (!permManager) {
+    return NS_ERROR_FAILURE;
+  }
+  uint32_t permission = nsIPermissionManager::UNKNOWN_ACTION;
+  nsresult rv = permManager->TestExactPermissionFromPrincipal(
+      aPrincipal, "desktop-notification"_ns, &permission);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  if (permission == nsIPermissionManager::ALLOW_ACTION ||
+      Preferences::GetBool("dom.push.testing.ignorePermission", false)) {
+    aState = PermissionState::Granted;
+  } else if (permission == nsIPermissionManager::DENY_ACTION) {
+    aState = PermissionState::Denied;
+  } else {
+    aState = PermissionState::Prompt;
+  }
+
+  return NS_OK;
+}
+
 class GetSubscriptionResultRunnable final : public WorkerThreadRunnable {
  public:
   GetSubscriptionResultRunnable(WorkerPrivate* aWorkerPrivate,

dom/push/PushManager.h

@@ -37,6 +37,7 @@
 
 class nsIGlobalObject;
 class nsIPrincipal;
+class nsIPushSubscription;
 
 namespace mozilla {
 class ErrorResult;
@@ -49,6 +50,12 @@ class PushManagerImpl;
 struct PushSubscriptionOptionsInit;
 class WorkerPrivate;
 
+nsresult GetSubscriptionParams(nsIPushSubscription* aSubscription,
+                               nsAString& aEndpoint,
+                               nsTArray<uint8_t>& aRawP256dhKey,
+                               nsTArray<uint8_t>& aAuthSecret,
+                               nsTArray<uint8_t>& aAppServerKey);
+
 class PushManager final : public nsISupports, public nsWrapperCache {
  public:
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS

dom/push/PushNotifier.cpp

@@ -9,6 +9,7 @@
 #include "nsContentUtils.h"
 #include "nsCOMPtr.h"
 #include "nsICategoryManager.h"
+#include "nsIPushService.h"
 #include "nsIXULRuntime.h"
 #include "nsNetUtil.h"
 #include "nsXPCOM.h"
@@ -66,9 +67,11 @@ PushNotifier::NotifyPush(const nsACString& aScope, nsIPrincipal* aPrincipal,
 
 NS_IMETHODIMP
 PushNotifier::NotifySubscriptionChange(const nsACString& aScope,
-                                       nsIPrincipal* aPrincipal) {
+                                       nsIPrincipal* aPrincipal,
+                                       nsIPushSubscription* aOldSubscription) {
   NS_ENSURE_ARG(aPrincipal);
-  PushSubscriptionChangeDispatcher dispatcher(aScope, aPrincipal);
+  PushSubscriptionChangeDispatcher dispatcher(aScope, aPrincipal,
+                                              aOldSubscription);
   return Dispatch(dispatcher);
 }
 
@@ -311,8 +314,9 @@ bool PushMessageDispatcher::SendToChild(ContentParent* aContentActor) {
 }
 
 PushSubscriptionChangeDispatcher::PushSubscriptionChangeDispatcher(
-    const nsACString& aScope, nsIPrincipal* aPrincipal)
+    const nsACString& aScope, nsIPrincipal* aPrincipal,
-    : PushDispatcher(aScope, aPrincipal) {}
+    nsIPushSubscription* aOldSubscription)
+    : PushDispatcher(aScope, aPrincipal), mOldSubscription(aOldSubscription) {}
 
 PushSubscriptionChangeDispatcher::~PushSubscriptionChangeDispatcher() = default;
 
@@ -334,7 +338,8 @@ nsresult PushSubscriptionChangeDispatcher::NotifyWorkers() {
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
-  return swm->SendPushSubscriptionChangeEvent(originSuffix, mScope);
+  return swm->SendPushSubscriptionChangeEvent(originSuffix, mScope,
+                                              mOldSubscription);
 }
 
 bool PushSubscriptionChangeDispatcher::SendToParent(

dom/push/PushNotifier.h

@@ -149,13 +149,17 @@ class PushMessageDispatcher final : public PushDispatcher {
 class PushSubscriptionChangeDispatcher final : public PushDispatcher {
  public:
   PushSubscriptionChangeDispatcher(const nsACString& aScope,
-                                   nsIPrincipal* aPrincipal);
+                                   nsIPrincipal* aPrincipal,
+                                   nsIPushSubscription* aOldSubscription);
   ~PushSubscriptionChangeDispatcher();
 
   nsresult NotifyObservers() override;
   nsresult NotifyWorkers() override;
   bool SendToParent(ContentChild* aParentActor) override;
   bool SendToChild(ContentParent* aContentActor) override;
+
+ private:
+  nsCOMPtr<nsIPushSubscription> mOldSubscription;
 };
 
 class PushSubscriptionModifiedDispatcher : public PushDispatcher {

dom/push/PushService.sys.mjs

@@ -4,6 +4,7 @@
 
 import { clearTimeout, setTimeout } from "resource://gre/modules/Timer.sys.mjs";
 import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+import { ChromePushSubscription } from "./ChromePushSubscription.sys.mjs";
 
 const lazy = {};
 
@@ -661,7 +662,11 @@ export var PushService = {
     if (!record) {
       return;
     }
-    lazy.gPushNotifier.notifySubscriptionChange(record.scope, record.principal);
+    lazy.gPushNotifier.notifySubscriptionChange(
+      record.scope,
+      record.principal,
+      new ChromePushSubscription(record.toSubscription())
+    );
   },
 
   /**

dom/push/moz.build

@@ -11,6 +11,7 @@ EXTRA_COMPONENTS += [
 ]
 
 EXTRA_JS_MODULES += [
+    "ChromePushSubscription.sys.mjs",
     "Push.sys.mjs",
     "PushBroadcastService.sys.mjs",
     "PushComponents.sys.mjs",

dom/push/test/xpcshell/test_handler_service.js

@@ -7,6 +7,9 @@
 const { MockRegistrar } = ChromeUtils.importESModule(
   "resource://testing-common/MockRegistrar.sys.mjs"
 );
+const { ChromePushSubscription } = ChromeUtils.importESModule(
+  "resource://gre/modules/ChromePushSubscription.sys.mjs"
+);
 
 let pushService = Cc["@mozilla.org/push/Service;1"].getService(
   Ci.nsIPushService
@@ -54,7 +57,21 @@ add_test(function test_service_instantiation() {
   equal(handlerService.observed[0].data, scope);
 
   // and a subscription change.
-  pushNotifier.notifySubscriptionChange(scope, principal);
+  pushNotifier.notifySubscriptionChange(
+    scope,
+    principal,
+    new ChromePushSubscription({
+      endpoint: "xpcshell",
+      lastPush: 0,
+      pushCount: 0,
+      p256dhKey: [],
+      p256dhPrivateKey: [],
+      authenticationSecret: [],
+      appServerKey: [],
+      quota: 0,
+      systemRecord: true,
+    })
+  );
   equal(handlerService.observed.length, 2);
   equal(handlerService.observed[1].topic, pushService.subscriptionChangeTopic);
   equal(handlerService.observed[1].subject, principal);

dom/serviceworkers/ServiceWorkerManager.cpp

@@ -21,6 +21,7 @@
 #include "nsServiceManagerUtils.h"
 #include "nsDebug.h"
 #include "nsIPermissionManager.h"
+#include "nsIPushService.h"
 #include "nsXULAppAPI.h"
 
 #include "jsapi.h"
@@ -1113,7 +1114,8 @@ nsresult ServiceWorkerManager::SendPushEvent(
 
 NS_IMETHODIMP
 ServiceWorkerManager::SendPushSubscriptionChangeEvent(
-    const nsACString& aOriginAttributes, const nsACString& aScope) {
+    const nsACString& aOriginAttributes, const nsACString& aScope,
+    nsIPushSubscription* aOldSubscription) {
   OriginAttributes attrs;
   if (!attrs.PopulateFromSuffix(aOriginAttributes)) {
     return NS_ERROR_INVALID_ARG;
@@ -1123,7 +1125,8 @@ ServiceWorkerManager::SendPushSubscriptionChangeEvent(
   if (!info) {
     return NS_ERROR_FAILURE;
   }
-  return info->WorkerPrivate()->SendPushSubscriptionChangeEvent();
+  return info->WorkerPrivate()->SendPushSubscriptionChangeEvent(
+      aOldSubscription);
 }
 
 nsresult ServiceWorkerManager::SendNotificationEvent(

dom/serviceworkers/ServiceWorkerOp.cpp

@@ -12,6 +12,8 @@
 #include "js/Exception.h"  // JS::ExceptionStack, JS::StealPendingExceptionStack
 #include "jsapi.h"
 
+#include "mozilla/dom/PushSubscriptionChangeEvent.h"
+#include "mozilla/dom/PushSubscriptionChangeEventBinding.h"
 #include "nsCOMPtr.h"
 #include "nsContentUtils.h"
 #include "nsDebug.h"
@@ -830,12 +832,28 @@ class PushSubscriptionChangeEventOp final : public ExtendableEventOp {
 
     RefPtr<EventTarget> target = aWorkerPrivate->GlobalScope();
 
-    ExtendableEventInit init;
+    ServiceWorkerPushSubscriptionChangeEventOpArgs& args =
+        mArgs.get_ServiceWorkerPushSubscriptionChangeEventOpArgs();
+
+    PushSubscriptionChangeEventInit init;
     init.mBubbles = false;
     init.mCancelable = false;
 
-    RefPtr<ExtendableEvent> event = ExtendableEvent::Constructor(
+    if (args.oldSubscription()) {
-        target, u"pushsubscriptionchange"_ns, init);
+      PushSubscriptionData oldSubscriptionData =
+          args.oldSubscription().extract();
+      RefPtr<PushSubscription> oldSubscription = new PushSubscription(
+          target->GetParentObject(), oldSubscriptionData.endpoint(), u""_ns,
+          Nullable<EpochTimeStamp>(),
+          std::move(oldSubscriptionData.rawP256dhKey()),
+          std::move(oldSubscriptionData.authSecret()),
+          std::move(oldSubscriptionData.appServerKey()));
+      init.mOldSubscription = oldSubscription.forget();
+    }
+
+    RefPtr<PushSubscriptionChangeEvent> event =
+        PushSubscriptionChangeEvent::Constructor(
+            target, u"pushsubscriptionchange"_ns, init);
     event->SetTrusted(true);
 
     nsresult rv = DispatchExtendableEventOnWorkerScope(

dom/serviceworkers/ServiceWorkerOpArgs.ipdlh

@@ -42,7 +42,16 @@ struct ServiceWorkerPushEventOpArgs {
   OptionalPushData data;
 };
 
-struct ServiceWorkerPushSubscriptionChangeEventOpArgs {};
+struct PushSubscriptionData {
+  nsString endpoint;
+  uint8_t[] rawP256dhKey;
+  uint8_t[] authSecret;
+  uint8_t[] appServerKey;
+};
+
+struct ServiceWorkerPushSubscriptionChangeEventOpArgs {
+  PushSubscriptionData? oldSubscription;
+};
 
 struct ServiceWorkerNotificationEventOpArgs {
   nsString eventName;

dom/serviceworkers/ServiceWorkerPrivate.cpp

@@ -38,6 +38,7 @@
 #include "mozilla/dom/FetchEventOpChild.h"
 #include "mozilla/dom/InternalHeaders.h"
 #include "mozilla/dom/InternalRequest.h"
+#include "mozilla/dom/PushManager.h"
 #include "mozilla/dom/ReferrerInfo.h"
 #include "mozilla/dom/RemoteType.h"
 #include "mozilla/dom/RemoteWorkerControllerChild.h"
@@ -970,12 +971,22 @@ nsresult ServiceWorkerPrivate::SendPushEventInternal(
       });
 }
 
-nsresult ServiceWorkerPrivate::SendPushSubscriptionChangeEvent() {
+nsresult ServiceWorkerPrivate::SendPushSubscriptionChangeEvent(
+    const RefPtr<nsIPushSubscription>& aOldSubscription) {
   AssertIsOnMainThread();
 
+  ServiceWorkerPushSubscriptionChangeEventOpArgs args{};
+  if (aOldSubscription) {
+    PushSubscriptionData oldSubscription{};
+    MOZ_TRY(GetSubscriptionParams(aOldSubscription, oldSubscription.endpoint(),
+                                  oldSubscription.rawP256dhKey(),
+                                  oldSubscription.authSecret(),
+                                  oldSubscription.appServerKey()));
+    args.oldSubscription().emplace(oldSubscription);
+  }
+
   return ExecServiceWorkerOp(
-      ServiceWorkerPushSubscriptionChangeEventOpArgs(),
+      std::move(args), ServiceWorkerLifetimeExtension(FullLifetimeExtension{}),
-      ServiceWorkerLifetimeExtension(FullLifetimeExtension{}),
       [](ServiceWorkerOpResult&& aResult) {
         MOZ_ASSERT(aResult.type() == ServiceWorkerOpResult::Tnsresult);
       });

dom/serviceworkers/ServiceWorkerPrivate.h

@@ -30,6 +30,7 @@
 #define NOTIFICATION_CLOSE_EVENT_NAME u"notificationclose"
 
 class nsIInterceptedChannel;
+class nsIPushSubscription;
 class nsIWorkerDebugger;
 
 namespace mozilla {
@@ -107,7 +108,8 @@ class ServiceWorkerPrivate final : public RemoteWorkerObserver {
                          const Maybe<nsTArray<uint8_t>>& aData,
                          RefPtr<ServiceWorkerRegistrationInfo> aRegistration);
 
-  nsresult SendPushSubscriptionChangeEvent();
+  nsresult SendPushSubscriptionChangeEvent(
+      const RefPtr<nsIPushSubscription>& aOldSubscription);
 
   nsresult SendNotificationEvent(const nsAString& aEventName,
                                  const nsAString& aID, const nsAString& aTitle,

testing/web-platform/mozilla/meta/push-api/__dir__.ini

@@ -0,0 +1 @@
+prefs: [dom.push.serverURL:wss://web-platform.test:8889/mozilla_push_dummy,dom.push.connection.enabled:true]

testing/web-platform/mozilla/meta/push-api/pushsubscriptionchange.https.any.js.ini

@@ -0,0 +1,4 @@
+[pushsubscriptionchange.https.any.window-module.html]
+  [Fire pushsubscriptionchange event when permission is revoked]
+    expected:
+      if os == "android": FAIL

testing/web-platform/mozilla/tests/push-api/push-sw.js

@@ -0,0 +1,15 @@
+async function postAll(data) {
+  const clients = await self.clients.matchAll({ includeUncontrolled: true });
+  for (const client of clients) {
+    client.postMessage(data);
+  }
+}
+
+onpushsubscriptionchange = ev => {
+  postAll({
+    type: ev.type,
+    constructor: ev.constructor.name,
+    oldSubscription: ev.oldSubscription?.toJSON(),
+    newSubscription: ev.newSubscription?.toJSON(),
+  });
+}

testing/web-platform/mozilla/tests/push-api/pushsubscriptionchange.https.any.js

@@ -0,0 +1,35 @@
+// META: global=window-module
+// META: script=/resources/testdriver.js
+// META: script=/resources/testdriver-vendor.js
+// META: script=/notifications/resources/helpers.js
+
+let registration;
+
+promise_setup(async () => {
+  await trySettingPermission("granted");
+  registration = await getActiveServiceWorker("push-sw.js");
+});
+
+promise_test(async (t) => {
+  const promise = new Promise(r => {
+    navigator.serviceWorker.addEventListener("message", r, { once: true })
+  });
+
+  const subscription = await registration.pushManager.subscribe();
+  t.add_cleanup(() => subscription.unsubscribe());
+
+  // https://w3c.github.io/push-api/#security-and-privacy-considerations
+  // When a permission is revoked, the user agent MAY fire the "pushsubscriptionchange"
+  // event for subscriptions created with that permission
+  //
+  // But Firefox fires pushsubscriptionchange on permission regrant instead of revocation.
+  // https://github.com/w3c/push-api/issues/236
+  await trySettingPermission("prompt");
+  await trySettingPermission("granted");
+
+  const pushSubscriptionChangeEvent = await promise;
+
+  assert_equals(pushSubscriptionChangeEvent.data.type, "pushsubscriptionchange");
+  assert_equals(pushSubscriptionChangeEvent.data.constructor, "PushSubscriptionChangeEvent");
+  assert_object_equals(pushSubscriptionChangeEvent.data.oldSubscription, subscription.toJSON());
+}, "Fire pushsubscriptionchange event when permission is revoked");