diff --git a/dom/workers/ServiceWorkerClients.h b/dom/workers/ServiceWorkerClients.h
index 39cf03a6dab6..a1ea870d294b 100644
--- a/dom/workers/ServiceWorkerClients.h
+++ b/dom/workers/ServiceWorkerClients.h
@@ -9,6 +9,7 @@
 
 #include "nsAutoPtr.h"
 #include "nsWrapperCache.h"
+#include "mozilla/dom/WorkerScope.h"
 
 namespace mozilla {
 
@@ -20,8 +21,6 @@ class Promise;
 
 namespace workers {
 
-class ServiceWorkerGlobalScope;
-
 class ServiceWorkerClients MOZ_FINAL : public nsISupports,
                                        public nsWrapperCache
 {
diff --git a/dom/workers/WorkerScope.cpp b/dom/workers/WorkerScope.cpp
index 015fd2ce3045..9a41031ab119 100644
--- a/dom/workers/WorkerScope.cpp
+++ b/dom/workers/WorkerScope.cpp
@@ -33,6 +33,7 @@
 #include "WorkerPrivate.h"
 #include "WorkerRunnable.h"
 #include "Performance.h"
+#include "ServiceWorkerClients.h"
 
 #define UNWRAP_WORKER_OBJECT(Interface, obj, value)                           \
   UnwrapObject<prototypes::id::Interface##_workers,                           \
@@ -374,6 +375,10 @@ ServiceWorkerGlobalScope::ServiceWorkerGlobalScope(WorkerPrivate* aWorkerPrivate
 {
 }
 
+ServiceWorkerGlobalScope::~ServiceWorkerGlobalScope()
+{
+}
+
 JSObject*
 ServiceWorkerGlobalScope::WrapGlobalObject(JSContext* aCx)
 {
@@ -388,6 +393,16 @@ ServiceWorkerGlobalScope::WrapGlobalObject(JSContext* aCx)
                                                        true);
 }
 
+ServiceWorkerClients*
+ServiceWorkerGlobalScope::Clients()
+{
+  if (!mClients) {
+    mClients = new ServiceWorkerClients(this);
+  }
+
+  return mClients;
+}
+
 bool
 GetterOnlyJSNative(JSContext* aCx, unsigned aArgc, JS::Value* aVp)
 {
diff --git a/dom/workers/WorkerScope.h b/dom/workers/WorkerScope.h
index f969fae0e85e..8f2ef1b29c4a 100644
--- a/dom/workers/WorkerScope.h
+++ b/dom/workers/WorkerScope.h
@@ -11,8 +11,6 @@
 #include "mozilla/dom/Headers.h"
 #include "mozilla/dom/RequestBinding.h"
 
-#include "ServiceWorkerClients.h"
-
 namespace mozilla {
 namespace dom {
 
@@ -26,6 +24,7 @@ class RequestOrScalarValueString;
 
 BEGIN_WORKERS_NAMESPACE
 
+class ServiceWorkerClients;
 class WorkerPrivate;
 class WorkerLocation;
 class WorkerNavigator;
@@ -174,7 +173,7 @@ class ServiceWorkerGlobalScope MOZ_FINAL : public WorkerGlobalScope
   const nsString mScope;
   nsRefPtr<ServiceWorkerClients> mClients;
 
-  ~ServiceWorkerGlobalScope() { }
+  ~ServiceWorkerGlobalScope();
 
 public:
   NS_DECL_ISUPPORTS_INHERITED
@@ -208,13 +207,7 @@ public:
   Unregister(ErrorResult& aRv);
 
   ServiceWorkerClients*
-  Clients() {
-    if (!mClients) {
-      mClients = new ServiceWorkerClients(this);
-    }
-
-    return mClients;
-  }
+  Clients();
 
   IMPL_EVENT_HANDLER(activate)
   IMPL_EVENT_HANDLER(beforeevicted)
@@ -229,4 +222,10 @@ CreateGlobalScope(JSContext* aCx);
 
 END_WORKERS_NAMESPACE
 
+inline nsISupports*
+ToSupports(mozilla::dom::workers::WorkerGlobalScope* aScope)
+{
+  return static_cast<nsIDOMEventTarget*>(aScope);
+}
+
 #endif /* mozilla_dom_workerscope_h__ */