Revert of Revert "Mojoify FetchEvent of Service Worker."

content/browser/service_worker/service_worker_fetch_dispatcher.cc

Index: content/browser/service_worker/service_worker_fetch_dispatcher.cc
diff --git a/content/browser/service_worker/service_worker_fetch_dispatcher.cc b/content/browser/service_worker/service_worker_fetch_dispatcher.cc
index 7d71218ea20a8d40d78047ee7aee788d5f6ac9d5..601f64fe3806c7c2492ddcac0aeee4405080b862 100644
--- a/content/browser/service_worker/service_worker_fetch_dispatcher.cc
+++ b/content/browser/service_worker/service_worker_fetch_dispatcher.cc
@@ -12,7 +12,9 @@
 #include "base/trace_event/trace_event.h"
 #include "content/browser/service_worker/embedded_worker_status.h"
 #include "content/browser/service_worker/service_worker_version.h"
+#include "content/common/service_worker/fetch_event_dispatcher.mojom.h"
 #include "content/common/service_worker/service_worker_messages.h"
+#include "content/common/service_worker/service_worker_status_code.h"
 #include "content/common/service_worker/service_worker_utils.h"
 #include "net/log/net_log.h"
 #include "net/log/net_log_capture_mode.h"
@@ -72,6 +74,14 @@
   if (type == ServiceWorkerFetchType::FOREIGN_FETCH)
     return ServiceWorkerMetrics::EventType::FOREIGN_FETCH_WAITUNTIL;
   return ServiceWorkerMetrics::EventType::FETCH_WAITUNTIL;
+}
+
+void OnFetchEventFinished(ServiceWorkerVersion* version,
+                          int event_finish_id,
+                          ServiceWorkerStatusCode status,
+                          base::Time dispatch_event_time) {
+  version->FinishRequest(event_finish_id, status != SERVICE_WORKER_ERROR_ABORT,
+                         dispatch_event_time);
 }
 
 }  // namespace
@@ -211,11 +221,16 @@
       response_id,
       base::Bind(&ServiceWorkerFetchDispatcher::ResponseCallback::Run,
                  base::Owned(response_callback)));
-  version_->RegisterSimpleRequest<ServiceWorkerHostMsg_FetchEventFinished>(
-      event_finish_id);
-  version_->DispatchEvent({response_id, event_finish_id},
-                          ServiceWorkerMsg_FetchEvent(
-                              response_id, event_finish_id, *request_.get()));
+
+  base::WeakPtr<mojom::FetchEventDispatcher> dispatcher =
+      version_->GetMojoServiceForRequest<mojom::FetchEventDispatcher>(
+          event_finish_id);
+  // |dispatcher| is owned by |version_|. So it is safe to pass the unretained
+  // raw pointer of |version_| to OnFetchEventFinished callback.
+  dispatcher->DispatchFetchEvent(
+      response_id, *request_,
+      base::Bind(&OnFetchEventFinished, base::Unretained(version_.get()),
+                 event_finish_id));
 }
 
 void ServiceWorkerFetchDispatcher::DidFailToDispatch(