Revert of [ServivceWorker] Treat rejecting respondWith as a Network Error

Source/modules/serviceworkers/RespondWithObserver.h

Index: Source/modules/serviceworkers/RespondWithObserver.h
diff --git a/Source/modules/serviceworkers/RespondWithObserver.h b/Source/modules/serviceworkers/RespondWithObserver.h
index 372a97b115519cfa62a4cf54846472986c8c9b9b..a7b9f29fcfa08fdf02ac26cf41d51106cc5e71c1 100644
--- a/Source/modules/serviceworkers/RespondWithObserver.h
+++ b/Source/modules/serviceworkers/RespondWithObserver.h
@@ -42,6 +42,10 @@
 
     RespondWithObserver(ExecutionContext*, int eventID);
 
+    // Sends a response back to the client. The null response means to fallback
+    // to native.
+    void sendResponse(Response*);
+
     int m_eventID;
 
     enum State { Initial, Pending, Done };