--- a/dom/serviceworkers/ServiceWorkerContainer.cpp
+++ b/dom/serviceworkers/ServiceWorkerContainer.cpp
@@ -19,16 +19,17 @@
 
 #include "mozilla/dom/DOMPrefs.h"
 #include "mozilla/dom/Navigator.h"
 #include "mozilla/dom/Promise.h"
 #include "mozilla/dom/ServiceWorker.h"
 #include "mozilla/dom/ServiceWorkerContainerBinding.h"
 
 #include "ServiceWorker.h"
+#include "ServiceWorkerContainerImpl.h"
 
 namespace mozilla {
 namespace dom {
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ServiceWorkerContainer)
 NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)
 
 NS_IMPL_ADDREF_INHERITED(ServiceWorkerContainer, DOMEventTargetHelper)
@@ -55,22 +56,26 @@ ServiceWorkerContainer::IsEnabled(JSCont
 
   return DOMPrefs::ServiceWorkersEnabled();
 }
 
 // static
 already_AddRefed<ServiceWorkerContainer>
 ServiceWorkerContainer::Create(nsIGlobalObject* aGlobal)
 {
-  RefPtr<ServiceWorkerContainer> ref = new ServiceWorkerContainer(aGlobal);
+  RefPtr<Inner> inner = new ServiceWorkerContainerImpl();
+  RefPtr<ServiceWorkerContainer> ref =
+    new ServiceWorkerContainer(aGlobal, inner.forget());
   return ref.forget();
 }
 
-ServiceWorkerContainer::ServiceWorkerContainer(nsIGlobalObject* aGlobal)
+ServiceWorkerContainer::ServiceWorkerContainer(nsIGlobalObject* aGlobal,
+                                               already_AddRefed<ServiceWorkerContainer::Inner> aInner)
   : DOMEventTargetHelper(aGlobal)
+  , mInner(aInner)
 {
   Maybe<ServiceWorkerDescriptor> controller = aGlobal->GetController();
   if (controller.isSome()) {
     mControllerWorker = aGlobal->GetOrCreateServiceWorker(controller.ref());
   }
 }
 
 ServiceWorkerContainer::~ServiceWorkerContainer()

--- a/dom/serviceworkers/ServiceWorkerContainer.h
+++ b/dom/serviceworkers/ServiceWorkerContainer.h
@@ -18,16 +18,35 @@ namespace dom {
 class Promise;
 struct RegistrationOptions;
 class ServiceWorker;
 
 // Lightweight serviceWorker APIs collection.
 class ServiceWorkerContainer final : public DOMEventTargetHelper
 {
 public:
+  class Inner
+  {
+  public:
+    virtual RefPtr<ServiceWorkerRegistrationPromise>
+    Register(const nsAString& aScriptURL,
+             const RegistrationOptions& aOptions) = 0;
+
+    virtual RefPtr<ServiceWorkerRegistrationPromise>
+    GetRegistration(const nsAString& aURL) = 0;
+
+    virtual RefPtr<ServiceWorkerRegistrationListPromise>
+    GetRegistrations() = 0;
+
+    virtual RefPtr<ServiceWorkerRegistrationPromise>
+    GetReady() = 0;
+
+    NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
+  };
+
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ServiceWorkerContainer, DOMEventTargetHelper)
 
   IMPL_EVENT_HANDLER(controllerchange)
   IMPL_EVENT_HANDLER(error)
   IMPL_EVENT_HANDLER(message)
 
   static bool IsEnabled(JSContext* aCx, JSObject* aGlobal);
@@ -64,20 +83,23 @@ public:
   void DisconnectFromOwner() override;
 
   // Invalidates |mControllerWorker| and dispatches a "controllerchange"
   // event.
   void
   ControllerChanged(ErrorResult& aRv);
 
 private:
-  explicit ServiceWorkerContainer(nsIGlobalObject* aGlobal);
+  ServiceWorkerContainer(nsIGlobalObject* aGlobal,
+                         already_AddRefed<ServiceWorkerContainer::Inner> aInner);
 
   ~ServiceWorkerContainer();
 
+  RefPtr<Inner> mInner;
+
   // This only changes when a worker hijacks everything in its scope by calling
   // claim.
   RefPtr<ServiceWorker> mControllerWorker;
 
   RefPtr<Promise> mReadyPromise;
   MozPromiseRequestHolder<ServiceWorkerRegistrationPromise> mReadyPromiseHolder;
 };
 

new file mode 100644
--- /dev/null
+++ b/dom/serviceworkers/ServiceWorkerContainerImpl.cpp
@@ -0,0 +1,42 @@
+/* -*- 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 "ServiceWorkerContainerImpl.h"
+
+namespace mozilla {
+namespace dom {
+
+RefPtr<ServiceWorkerRegistrationPromise>
+ServiceWorkerContainerImpl::Register(const nsAString& aScriptURL,
+                                     const RegistrationOptions& aOptions)
+{
+  // TODO
+  return nullptr;
+}
+
+RefPtr<ServiceWorkerRegistrationPromise>
+ServiceWorkerContainerImpl::GetRegistration(const nsAString& aURL)
+{
+  // TODO
+  return nullptr;
+}
+
+RefPtr<ServiceWorkerRegistrationListPromise>
+ServiceWorkerContainerImpl::GetRegistrations()
+{
+  // TODO
+  return nullptr;
+}
+
+RefPtr<ServiceWorkerRegistrationPromise>
+ServiceWorkerContainerImpl::GetReady()
+{
+  // TODO
+  return nullptr;
+}
+
+} // namespace dom
+} // namespace mozilla

new file mode 100644
--- /dev/null
+++ b/dom/serviceworkers/ServiceWorkerContainerImpl.h
@@ -0,0 +1,40 @@
+/* -*- 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_serviceworkercontainerimpl_h__
+#define mozilla_dom_serviceworkercontainerimpl_h__
+
+#include "ServiceWorkerContainer.h"
+
+namespace mozilla {
+namespace dom {
+
+// Lightweight serviceWorker APIs collection.
+class ServiceWorkerContainerImpl final : public ServiceWorkerContainer::Inner
+{
+  ~ServiceWorkerContainerImpl() = default;
+
+public:
+  RefPtr<ServiceWorkerRegistrationPromise>
+  Register(const nsAString& aScriptURL,
+           const RegistrationOptions& aOptions) override;
+
+  RefPtr<ServiceWorkerRegistrationPromise>
+  GetRegistration(const nsAString& aURL) override;
+
+  RefPtr<ServiceWorkerRegistrationListPromise>
+  GetRegistrations() override;
+
+  RefPtr<ServiceWorkerRegistrationPromise>
+  GetReady() override;
+
+  NS_INLINE_DECL_REFCOUNTING(ServiceWorkerContainerImpl, override)
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif /* mozilla_dom_serviceworkercontainerimpl_h__ */

--- a/dom/serviceworkers/ServiceWorkerRegistrationImpl.h
+++ b/dom/serviceworkers/ServiceWorkerRegistrationImpl.h
@@ -1,14 +1,17 @@
 /* -*- 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_serviceworkerregistrationimpl_h
+#define mozilla_dom_serviceworkerregistrationimpl_h
+
 #include "mozilla/dom/WorkerPrivate.h"
 #include "mozilla/Unused.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsIDocument.h"
 #include "nsPIDOMWindow.h"
 #include "ServiceWorkerManager.h"
 #include "ServiceWorkerRegistration.h"
 #include "ServiceWorkerRegistrationListener.h"
@@ -156,8 +159,10 @@ private:
   ServiceWorkerRegistration* mOuter;
   const nsString mScope;
   RefPtr<WorkerListener> mListener;
   RefPtr<WeakWorkerRef> mWorkerRef;
 };
 
 } // dom namespace
 } // mozilla namespace
+
+#endif // mozilla_dom_serviceworkerregistrationimpl_h

--- a/dom/serviceworkers/ServiceWorkerUtils.h
+++ b/dom/serviceworkers/ServiceWorkerUtils.h
@@ -3,26 +3,30 @@
 /* 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_ServiceWorkerUtils_h
 #define _mozilla_dom_ServiceWorkerUtils_h
 
 #include "mozilla/MozPromise.h"
 #include "mozilla/dom/ServiceWorkerRegistrationDescriptor.h"
+#include "nsTArray.h"
 
 namespace mozilla {
 namespace dom {
 
 class ServiceWorkerRegistrationData;
 class ServiceWorkerRegistrationDescriptor;
 
 typedef MozPromise<ServiceWorkerRegistrationDescriptor, nsresult, false>
         ServiceWorkerRegistrationPromise;
 
+typedef MozPromise<nsTArray<ServiceWorkerRegistrationDescriptor>, nsresult, false>
+        ServiceWorkerRegistrationListPromise;
+
 bool
 ServiceWorkerParentInterceptEnabled();
 
 bool
 ServiceWorkerRegistrationDataIsValid(const ServiceWorkerRegistrationData& aData);
 
 } // namespace dom
 } // namespace mozilla

--- a/dom/serviceworkers/moz.build
+++ b/dom/serviceworkers/moz.build
@@ -24,16 +24,17 @@ EXPORTS.mozilla.dom += [
     'ServiceWorkerRegistrationDescriptor.h',
     'ServiceWorkerRegistrationInfo.h',
     'ServiceWorkerUtils.h',
 ]
 
 UNIFIED_SOURCES += [
     'ServiceWorker.cpp',
     'ServiceWorkerContainer.cpp',
+    'ServiceWorkerContainerImpl.cpp',
     'ServiceWorkerDescriptor.cpp',
     'ServiceWorkerEvents.cpp',
     'ServiceWorkerInfo.cpp',
     'ServiceWorkerInterceptController.cpp',
     'ServiceWorkerJob.cpp',
     'ServiceWorkerJobQueue.cpp',
     'ServiceWorkerManager.cpp',
     'ServiceWorkerManagerChild.cpp',