ServiceWorker: Bypass SW when the script doesn't have fetch handler

content/browser/service_worker/service_worker_controllee_request_handler.cc

Index: content/browser/service_worker/service_worker_controllee_request_handler.cc
diff --git a/content/browser/service_worker/service_worker_controllee_request_handler.cc b/content/browser/service_worker/service_worker_controllee_request_handler.cc
index 7b9b35c2f65f13ebd0b38aab55b6107763f09df3..1187e94b3c0af5e11cd92a30733303c54dd10fcc 100644
--- a/content/browser/service_worker/service_worker_controllee_request_handler.cc
+++ b/content/browser/service_worker/service_worker_controllee_request_handler.cc
@@ -26,6 +26,23 @@
 
 namespace content {
 
+namespace {
+
+bool MaybeForwardToServiceWorker(ServiceWorkerURLRequestJob* job,
+                                 const ServiceWorkerVersion* version) {
+  DCHECK(job);
+  DCHECK(version);
+  if (version->has_fetch_handler()) {
+    job->ForwardToServiceWorker();
+    return true;
+  }
+
+  job->FallbackToNetwork();
+  return false;
+}
+
+}  // namespace
+
 ServiceWorkerControlleeRequestHandler::ServiceWorkerControlleeRequestHandler(
     base::WeakPtr<ServiceWorkerContextCore> context,
     base::WeakPtr<ServiceWorkerProviderHost> provider_host,
@@ -251,15 +268,15 @@ ServiceWorkerControlleeRequestHandler::DidLookupRegistrationForMainResource(
   }
 
   ServiceWorkerMetrics::CountControlledPageLoad(stripped_url_);
+  bool is_forwarded =
+      MaybeForwardToServiceWorker(job_.get(), active_version.get());
 
-  job_->ForwardToServiceWorker();
   TRACE_EVENT_ASYNC_END2(
       "ServiceWorker",
       "ServiceWorkerControlleeRequestHandler::PrepareForMainResource",
-      job_.get(),
-      "Status", status,
-      "Info",
-      "Forwarded to the ServiceWorker");
+      job_.get(), "Status", status, "Info",
+      (is_forwarded) ? "Forwarded to the ServiceWorker"
+                     : "Skipped the ServiceWorker which has no fetch handler");
 }
 
 void ServiceWorkerControlleeRequestHandler::OnVersionStatusChanged(
@@ -282,7 +299,8 @@ void ServiceWorkerControlleeRequestHandler::OnVersionStatusChanged(
 
   provider_host_->AssociateRegistration(registration,
                                         false /* notify_controllerchange */);
-  job_->ForwardToServiceWorker();
+
+  MaybeForwardToServiceWorker(job_.get(), version);
 }
 
 void ServiceWorkerControlleeRequestHandler::DidUpdateRegistration(
@@ -352,7 +370,7 @@ void ServiceWorkerControlleeRequestHandler::PrepareForSubResource() {
   DCHECK(job_.get());
   DCHECK(context_);
   DCHECK(provider_host_->active_version());
-  job_->ForwardToServiceWorker();
+  MaybeForwardToServiceWorker(job_.get(), provider_host_->active_version());
 }
 
 void ServiceWorkerControlleeRequestHandler::OnPrepareToRestart() {