--- a/dom/workers/ServiceWorkerClients.h
+++ b/dom/workers/ServiceWorkerClients.h
@@ -4,29 +4,28 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
 #ifndef mozilla_dom_workers_serviceworkerclients_h
 #define mozilla_dom_workers_serviceworkerclients_h
 
 #include "nsAutoPtr.h"
 #include "nsWrapperCache.h"
+#include "mozilla/dom/WorkerScope.h"
 
 namespace mozilla {
 
 class ErrorResult;
 
 namespace dom {
 
 class Promise;
 
 namespace workers {
 
-class ServiceWorkerGlobalScope;
-
 class ServiceWorkerClients MOZ_FINAL : public nsISupports,
                                        public nsWrapperCache
 {
 public:
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(ServiceWorkerClients)
 
   ServiceWorkerClients(ServiceWorkerGlobalScope* aWorkerScope);

--- a/dom/workers/WorkerScope.cpp
+++ b/dom/workers/WorkerScope.cpp
@@ -28,16 +28,17 @@
 #include "Location.h"
 #include "Navigator.h"
 #include "Principal.h"
 #include "RuntimeService.h"
 #include "ScriptLoader.h"
 #include "WorkerPrivate.h"
 #include "WorkerRunnable.h"
 #include "Performance.h"
+#include "ServiceWorkerClients.h"
 
 #define UNWRAP_WORKER_OBJECT(Interface, obj, value)                           \
   UnwrapObject<prototypes::id::Interface##_workers,                           \
     mozilla::dom::Interface##Binding_workers::NativeType>(obj, value)
 
 using namespace mozilla;
 using namespace mozilla::dom;
 USING_WORKERS_NAMESPACE
@@ -369,30 +370,44 @@ NS_IMPL_RELEASE_INHERITED(ServiceWorkerG
 
 ServiceWorkerGlobalScope::ServiceWorkerGlobalScope(WorkerPrivate* aWorkerPrivate,
                                                    const nsACString& aScope)
   : WorkerGlobalScope(aWorkerPrivate),
     mScope(NS_ConvertUTF8toUTF16(aScope))
 {
 }
 
+ServiceWorkerGlobalScope::~ServiceWorkerGlobalScope()
+{
+}
+
 JSObject*
 ServiceWorkerGlobalScope::WrapGlobalObject(JSContext* aCx)
 {
   mWorkerPrivate->AssertIsOnWorkerThread();
   MOZ_ASSERT(mWorkerPrivate->IsServiceWorker());
 
   JS::CompartmentOptions options;
   mWorkerPrivate->CopyJSCompartmentOptions(options);
 
   return ServiceWorkerGlobalScopeBinding_workers::Wrap(aCx, this, this, options,
                                                        GetWorkerPrincipal(),
                                                        true);
 }
 
+ServiceWorkerClients*
+ServiceWorkerGlobalScope::Clients()
+{
+  if (!mClients) {
+    mClients = new ServiceWorkerClients(this);
+  }
+
+  return mClients;
+}
+
 bool
 GetterOnlyJSNative(JSContext* aCx, unsigned aArgc, JS::Value* aVp)
 {
   JS_ReportErrorNumber(aCx, js_GetErrorMessage, nullptr, JSMSG_GETTER_ONLY);
   return false;
 }
 
 namespace {

--- a/dom/workers/WorkerScope.h
+++ b/dom/workers/WorkerScope.h
@@ -6,31 +6,30 @@
 #ifndef mozilla_dom_workerscope_h__
 #define mozilla_dom_workerscope_h__
 
 #include "Workers.h"
 #include "mozilla/DOMEventTargetHelper.h"
 #include "mozilla/dom/Headers.h"
 #include "mozilla/dom/RequestBinding.h"
 
-#include "ServiceWorkerClients.h"
-
 namespace mozilla {
 namespace dom {
 
 class Console;
 class Function;
 class Promise;
 class RequestOrScalarValueString;
 
 } // namespace dom
 } // namespace mozilla
 
 BEGIN_WORKERS_NAMESPACE
 
+class ServiceWorkerClients;
 class WorkerPrivate;
 class WorkerLocation;
 class WorkerNavigator;
 class Performance;
 
 class WorkerGlobalScope : public DOMEventTargetHelper,
                           public nsIGlobalObject
 {
@@ -169,17 +168,17 @@ public:
   IMPL_EVENT_HANDLER(connect)
 };
 
 class ServiceWorkerGlobalScope MOZ_FINAL : public WorkerGlobalScope
 {
   const nsString mScope;
   nsRefPtr<ServiceWorkerClients> mClients;
 
-  ~ServiceWorkerGlobalScope() { }
+  ~ServiceWorkerGlobalScope();
 
 public:
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ServiceWorkerGlobalScope,
                                            WorkerGlobalScope)
 
   ServiceWorkerGlobalScope(WorkerPrivate* aWorkerPrivate, const nsACString& aScope);
 
@@ -203,30 +202,30 @@ public:
   {
     // FIXME(nsm): Bug 982728
   }
 
   already_AddRefed<Promise>
   Unregister(ErrorResult& aRv);
 
   ServiceWorkerClients*
-  Clients() {
-    if (!mClients) {
-      mClients = new ServiceWorkerClients(this);
-    }
-
-    return mClients;
-  }
+  Clients();
 
   IMPL_EVENT_HANDLER(activate)
   IMPL_EVENT_HANDLER(beforeevicted)
   IMPL_EVENT_HANDLER(evicted)
   IMPL_EVENT_HANDLER(fetch)
   IMPL_EVENT_HANDLER(install)
   IMPL_EVENT_HANDLER(message)
 };
 
 JSObject*
 CreateGlobalScope(JSContext* aCx);
 
 END_WORKERS_NAMESPACE
 
+inline nsISupports*
+ToSupports(mozilla::dom::workers::WorkerGlobalScope* aScope)
+{
+  return static_cast<nsIDOMEventTarget*>(aScope);
+}
+
 #endif /* mozilla_dom_workerscope_h__ */