Tests for WaitUntilObserver and focus/openining windows.

Source/modules/serviceworkers/WaitUntilObserver.h

Index: Source/modules/serviceworkers/WaitUntilObserver.h
diff --git a/Source/modules/serviceworkers/WaitUntilObserver.h b/Source/modules/serviceworkers/WaitUntilObserver.h
index b95e68f69599b9ca9dcf54406afacc03a584bd3c..6a4b733b7cdf8007f79c3f474f89e3d09df52e3a 100644
--- a/Source/modules/serviceworkers/WaitUntilObserver.h
+++ b/Source/modules/serviceworkers/WaitUntilObserver.h
@@ -42,6 +42,7 @@ public:
     virtual void trace(Visitor*) override;
 
 private:
+    friend class InternalsServiceWorker;
     class ThenFunction;
 
     WaitUntilObserver(ExecutionContext*, EventType, int eventID);
@@ -53,6 +54,8 @@ private:
 
     void consumeWindowInteraction(Timer<WaitUntilObserver>*);
 
+    static void overrideWindowInteractionTimeoutForTest(unsigned timeout);
+
     EventType m_type;
     int m_eventID;
     int m_pendingActivity;