Make sure notification permissions are granted before calling getToken

packages/functions/src/context.ts

@@ -85,16 +85,16 @@ export class ContextProvider {
   }
 
   async getInstanceIdToken(): Promise<string | undefined> {
-    try {
-      if (!this.messaging) {
-        return undefined;
-      }
+    if (
+      !this.messaging ||
+      !('Notification' in self) ||
+      Notification.permission !== 'granted'
+    ) {
+      return undefined;
+    }
 
-      const token = await this.messaging.getToken();
-      if (!token) {
-        return undefined;
-      }
-      return token;
+    try {
+      return this.messaging.getToken();
     } catch (e) {
       // We don't warn on this, because it usually means messaging isn't set up.
       // console.warn('Failed to retrieve instance id token.', e);

packages/functions/test/browser/callable.test.ts

@@ -64,6 +64,7 @@ describe('Firebase Functions > Call', () => {
 
     // Stub out the messaging method get an instance id token.
     const stub = sinon.stub(messagingMock, 'getToken').callThrough();
+    sinon.stub(Notification, 'permission').value('granted');
 
     const func = functions.httpsCallable('instanceIdTest');
     const result = await func({});