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

Source/modules/push_messaging/PushSubscriptionCallbacks.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PushSubscriptionCallbacks_h
 #define PushSubscriptionCallbacks_h
 
 #include "platform/heap/Handle.h"
 #include "public/platform/modules/push_messaging/WebPushProvider.h"
 #include "wtf/Noncopyable.h"
 
 namespace blink {
 
 class ServiceWorkerRegistration;
 class ScriptPromiseResolver;
 struct WebPushError;
 struct WebPushSubscription;
 
 // PushSubscriptionCallbacks is an implementation of WebPushSubscriptionCallbacks
 // that will resolve the underlying promise depending on the result passed to
 // the callback. It takes a ServiceWorkerRegistration in its constructor and
 // 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;
 
     void onSuccess(WebPassOwnPtr<WebPushSubscription>) override;
     void onError(const WebPushError&) override;
 
 private:
     Persistent<ScriptPromiseResolver> m_resolver;
     Persistent<ServiceWorkerRegistration> m_serviceWorkerRegistration;
 };
 
 } // namespace blink
 
 #endif // PushSubscriptionCallbacks_h