[part 2] Make classes and structures in modules fast-allocated.

Source/modules/push_messaging/PushSubscriptionCallbacks.h

Index: Source/modules/push_messaging/PushSubscriptionCallbacks.h
diff --git a/Source/modules/push_messaging/PushSubscriptionCallbacks.h b/Source/modules/push_messaging/PushSubscriptionCallbacks.h
index c9244875b16d48ab822bc7a6a498f9223c54b293..bdff38ead4647397ee6f2f3f4f3df53983162ce9 100644
--- a/Source/modules/push_messaging/PushSubscriptionCallbacks.h
+++ b/Source/modules/push_messaging/PushSubscriptionCallbacks.h
@@ -22,6 +22,7 @@ struct WebPushSubscription;
 // will pass it to the PushSubscription.
 class PushSubscriptionCallbacks final : public WebPushSubscriptionCallbacks {
     WTF_MAKE_NONCOPYABLE(PushSubscriptionCallbacks);
+    WTF_MAKE_FAST_ALLOCATED(PushSubscriptionCallbacks);
 public:
     PushSubscriptionCallbacks(ScriptPromiseResolver*, ServiceWorkerRegistration*);
     ~PushSubscriptionCallbacks() override;