service worker: Add CHECKs for investigating null http info bug.

content/browser/service_worker/embedded_worker_test_helper.h

Index: content/browser/service_worker/embedded_worker_test_helper.h
diff --git a/content/browser/service_worker/embedded_worker_test_helper.h b/content/browser/service_worker/embedded_worker_test_helper.h
index 3d58bbad571a0fecef5e53fe311644debfe985cf..26ad3905396f1ddc61bd67f0f487d61aac9f398d 100644
--- a/content/browser/service_worker/embedded_worker_test_helper.h
+++ b/content/browser/service_worker/embedded_worker_test_helper.h
@@ -23,6 +23,7 @@
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_test_sink.h"
 #include "mojo/public/cpp/bindings/binding.h"
+#include "net/http/http_response_info.h"
 #include "services/service_manager/public/cpp/interface_provider.h"
 #include "services/service_manager/public/cpp/interface_registry.h"
 #include "services/service_manager/public/interfaces/interface_provider.mojom.h"
@@ -154,6 +155,8 @@ class EmbeddedWorkerTestHelper : public IPC::Sender,
     return weak_factory_.GetWeakPtr();
   }
 
+  static net::HttpResponseInfo CreateHttpResponseInfo();
+
  protected:
   // Called when StartWorker, StopWorker and SendMessageToWorker message
   // is sent to the embedded worker. Override if necessary. By default