diff --git a/dom/serviceworkers/ServiceWorkerRegistrationImpl.cpp b/dom/serviceworkers/ServiceWorkerRegistrationImpl.cpp
index 78ec762daf21..f03517d33ba5 100644
--- a/dom/serviceworkers/ServiceWorkerRegistrationImpl.cpp
+++ b/dom/serviceworkers/ServiceWorkerRegistrationImpl.cpp
@@ -26,6 +26,7 @@
 #include "ServiceWorkerManager.h"
 #include "ServiceWorkerPrivate.h"
 #include "ServiceWorkerRegistration.h"
+#include "ServiceWorkerUnregisterCallback.h"
 
 #include "nsIDocument.h"
 #include "nsIServiceWorkerManager.h"
@@ -394,44 +395,6 @@ private:
 
 NS_IMPL_ISUPPORTS(SWRUpdateRunnable::TimerCallback, nsITimerCallback)
 
-class UnregisterCallback final : public nsIServiceWorkerUnregisterCallback
-{
-  RefPtr<GenericPromise::Private> mPromise;
-
-public:
-  NS_DECL_ISUPPORTS
-
-  UnregisterCallback()
-    : mPromise(new GenericPromise::Private(__func__))
-  {
-  }
-
-  NS_IMETHOD
-  UnregisterSucceeded(bool aState) override
-  {
-    mPromise->Resolve(aState, __func__);
-    return NS_OK;
-  }
-
-  NS_IMETHOD
-  UnregisterFailed() override
-  {
-    mPromise->Reject(NS_ERROR_DOM_SECURITY_ERR, __func__);
-    return NS_OK;
-  }
-
-  RefPtr<GenericPromise>
-  Promise() const
-  {
-    return mPromise;
-  }
-
-private:
-  ~UnregisterCallback() = default;
-};
-
-NS_IMPL_ISUPPORTS(UnregisterCallback, nsIServiceWorkerUnregisterCallback)
-
 class WorkerUnregisterCallback final : public nsIServiceWorkerUnregisterCallback
 {
   RefPtr<ThreadSafeWorkerRef> mWorkerRef;
diff --git a/dom/serviceworkers/ServiceWorkerRegistrationProxy.cpp b/dom/serviceworkers/ServiceWorkerRegistrationProxy.cpp
index 50437db81c30..bdd8c4d21df7 100644
--- a/dom/serviceworkers/ServiceWorkerRegistrationProxy.cpp
+++ b/dom/serviceworkers/ServiceWorkerRegistrationProxy.cpp
@@ -9,6 +9,7 @@
 #include "mozilla/ipc/BackgroundParent.h"
 #include "ServiceWorkerManager.h"
 #include "ServiceWorkerRegistrationParent.h"
+#include "ServiceWorkerUnregisterCallback.h"
 
 namespace mozilla {
 namespace dom {
@@ -170,42 +171,6 @@ ServiceWorkerRegistrationProxy::RevokeActor(ServiceWorkerRegistrationParent* aAc
   MOZ_ALWAYS_SUCCEEDS(SystemGroup::Dispatch(TaskCategory::Other, r.forget()));
 }
 
-namespace {
-
-class UnregisterCallback final : public nsIServiceWorkerUnregisterCallback
-{
-  RefPtr<GenericPromise::Private> mPromise;
-
-  ~UnregisterCallback() = default;
-
-public:
-  explicit UnregisterCallback(GenericPromise::Private* aPromise)
-    : mPromise(aPromise)
-  {
-    MOZ_DIAGNOSTIC_ASSERT(mPromise);
-  }
-
-  NS_IMETHOD
-  UnregisterSucceeded(bool aState) override
-  {
-    mPromise->Resolve(aState, __func__);
-    return NS_OK;
-  }
-
-  NS_IMETHOD
-  UnregisterFailed() override
-  {
-    mPromise->Reject(NS_ERROR_DOM_SECURITY_ERR, __func__);
-    return NS_OK;
-  }
-
-  NS_DECL_ISUPPORTS
-};
-
-NS_IMPL_ISUPPORTS(UnregisterCallback, nsIServiceWorkerUnregisterCallback)
-
-} // anonymous namespace
-
 RefPtr<GenericPromise>
 ServiceWorkerRegistrationProxy::Unregister()
 {
diff --git a/dom/serviceworkers/ServiceWorkerUnregisterCallback.cpp b/dom/serviceworkers/ServiceWorkerUnregisterCallback.cpp
new file mode 100644
index 000000000000..ddc334dd51a0
--- /dev/null
+++ b/dom/serviceworkers/ServiceWorkerUnregisterCallback.cpp
@@ -0,0 +1,44 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#include "ServiceWorkerUnregisterCallback.h"
+
+namespace mozilla {
+namespace dom {
+
+NS_IMPL_ISUPPORTS(UnregisterCallback, nsIServiceWorkerUnregisterCallback)
+
+UnregisterCallback::UnregisterCallback()
+  : mPromise(new GenericPromise::Private(__func__)) {}
+
+UnregisterCallback::UnregisterCallback(GenericPromise::Private* aPromise)
+  : mPromise(aPromise)
+{
+  MOZ_DIAGNOSTIC_ASSERT(mPromise);
+}
+
+NS_IMETHODIMP
+UnregisterCallback::UnregisterSucceeded(bool aState)
+{
+  mPromise->Resolve(aState, __func__);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+UnregisterCallback::UnregisterFailed()
+{
+  mPromise->Reject(NS_ERROR_DOM_SECURITY_ERR, __func__);
+  return NS_OK;
+}
+
+RefPtr<GenericPromise>
+UnregisterCallback::Promise() const
+{
+  return mPromise;
+}
+
+} // namespace dom
+} // namespace mozilla
diff --git a/dom/serviceworkers/ServiceWorkerUnregisterCallback.h b/dom/serviceworkers/ServiceWorkerUnregisterCallback.h
new file mode 100644
index 000000000000..1a7dacc79085
--- /dev/null
+++ b/dom/serviceworkers/ServiceWorkerUnregisterCallback.h
@@ -0,0 +1,45 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#ifndef mozilla_dom_ServiceWorkerUnregisterCallback_h
+#define mozilla_dom_ServiceWorkerUnregisterCallback_h
+
+#include "mozilla/MozPromise.h"
+#include "mozilla/RefPtr.h"
+#include "nsIServiceWorkerManager.h"
+
+namespace mozilla {
+namespace dom {
+
+class UnregisterCallback final : public nsIServiceWorkerUnregisterCallback
+{
+ public:
+   NS_DECL_ISUPPORTS
+
+   UnregisterCallback();
+
+   explicit UnregisterCallback(GenericPromise::Private* aPromise);
+
+   // nsIServiceWorkerUnregisterCallback implementation
+   NS_IMETHOD
+   UnregisterSucceeded(bool aState) override;
+
+   NS_IMETHOD
+   UnregisterFailed() override;
+
+   RefPtr<GenericPromise>
+   Promise() const;
+
+ private:
+  ~UnregisterCallback() = default;
+
+  RefPtr<GenericPromise::Private> mPromise;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_ServiceWorkerUnregisterCallback_h
diff --git a/dom/serviceworkers/moz.build b/dom/serviceworkers/moz.build
index f62a80866e33..8a0780f65e99 100644
--- a/dom/serviceworkers/moz.build
+++ b/dom/serviceworkers/moz.build
@@ -64,6 +64,7 @@ UNIFIED_SOURCES += [
     'ServiceWorkerRegistrationParent.cpp',
     'ServiceWorkerRegistrationProxy.cpp',
     'ServiceWorkerScriptCache.cpp',
+    'ServiceWorkerUnregisterCallback.cpp',
     'ServiceWorkerUnregisterJob.cpp',
     'ServiceWorkerUpdateJob.cpp',
     'ServiceWorkerUpdaterChild.cpp',