Simplify ServiceWorkerContainer's access to its window.

Source/modules/serviceworkers/ServiceWorkerContainer.h

Index: Source/modules/serviceworkers/ServiceWorkerContainer.h
diff --git a/Source/modules/serviceworkers/ServiceWorkerContainer.h b/Source/modules/serviceworkers/ServiceWorkerContainer.h
index d098ff775b1609770014b9f95c5e8ee756da9958..abd778466b33141ddf9d8db4fa0e33463d75fd9a 100644
--- a/Source/modules/serviceworkers/ServiceWorkerContainer.h
+++ b/Source/modules/serviceworkers/ServiceWorkerContainer.h
@@ -34,7 +34,6 @@
 #include "bindings/v8/ScriptPromise.h"
 #include "bindings/v8/ScriptWrappable.h"
 #include "core/dom/ContextLifecycleObserver.h"
-#include "core/frame/DOMWindowLifecycleObserver.h"
 #include "modules/serviceworkers/ServiceWorker.h"
 #include "public/platform/WebServiceWorkerProviderClient.h"
 #include "wtf/Forward.h"
@@ -56,7 +55,6 @@ class ServiceWorkerContainer FINAL :
     public RefCounted<ServiceWorkerContainer>,
     public ScriptWrappable,
     public ContextLifecycleObserver,
-    public DOMWindowLifecycleObserver,
     public blink::WebServiceWorkerProviderClient {
 public:
     static PassRefPtr<ServiceWorkerContainer> create(ExecutionContext*);