[POC-WIP] Link window focus tokens with ExecutionContext.

Source/modules/serviceworkers/ServiceWorkerGlobalScopeClient.h

Index: Source/modules/serviceworkers/ServiceWorkerGlobalScopeClient.h
diff --git a/Source/modules/serviceworkers/ServiceWorkerGlobalScopeClient.h b/Source/modules/serviceworkers/ServiceWorkerGlobalScopeClient.h
index cd45f77f59368d777b27dc168b4c79f28ecf2d10..5cdafb4afb89f64f9b43f5d4ad6785152568c9c5 100644
--- a/Source/modules/serviceworkers/ServiceWorkerGlobalScopeClient.h
+++ b/Source/modules/serviceworkers/ServiceWorkerGlobalScopeClient.h
@@ -34,6 +34,7 @@
 #include "core/dom/MessagePort.h"
 #include "core/workers/WorkerClients.h"
 #include "public/platform/WebMessagePortChannel.h"
+#include "public/platform/WebServiceWorkerClientFocusCallback.h"
 #include "public/platform/WebServiceWorkerClientsInfo.h"
 #include "public/platform/WebServiceWorkerEventResult.h"
 #include "public/platform/WebServiceWorkerSkipWaitingCallbacks.h"
@@ -68,6 +69,7 @@ public:
     virtual void didHandleSyncEvent(int syncEventID) = 0;
     virtual void postMessageToClient(int clientID, const WebString& message, PassOwnPtr<WebMessagePortChannelArray>) = 0;
     virtual void skipWaiting(WebServiceWorkerSkipWaitingCallbacks*) = 0;
+    virtual void focus(int clientID, WebServiceWorkerClientFocusCallback*) = 0;
 
     static const char* supplementName();
     static ServiceWorkerGlobalScopeClient* from(ExecutionContext*);