Add IPC stubs between browser and ServiceWorker's worker context in the child process

content/renderer/service_worker/service_worker_context_client.h

Index: content/renderer/service_worker/service_worker_context_client.h
diff --git a/content/renderer/service_worker/service_worker_context_client.h b/content/renderer/service_worker/service_worker_context_client.h
index e59cc62a84ad73932d45de93fc677f9a4141a5f2..18b4fec569c59ca7e97f6488774b80cb1b37c874 100644
--- a/content/renderer/service_worker/service_worker_context_client.h
+++ b/content/renderer/service_worker/service_worker_context_client.h
@@ -17,6 +17,7 @@ class MessageLoopProxy;
 
 namespace content {
 
+struct ServiceWorkerFetchRequest;
 class ThreadSafeSender;
 
 // This class provides access to/from an embedded worker's WorkerGlobalScope.
@@ -47,6 +48,10 @@ class ServiceWorkerContextClient
   int embedded_worker_id() const { return embedded_worker_id_; }
 
  private:
+  void OnFetchEvent(int thread_id,
+                    int embedded_worker_id,
+                    const ServiceWorkerFetchRequest& request);
+
   const int embedded_worker_id_;
   const int64 service_worker_version_id_;
   const GURL script_url_;