ServiceWorker: Insert TRACE_EVENT to watch a breakdown of the ServiceWorker's performance on chome:…

content/browser/service_worker/service_worker_controllee_request_handler.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/service_worker/service_worker_controllee_request_handler.h"
 
+#include "base/debug/trace_event.h"
 #include "content/browser/service_worker/service_worker_context_core.h"
 #include "content/browser/service_worker/service_worker_metrics.h"
 #include "content/browser/service_worker/service_worker_provider_host.h"
 #include "content/browser/service_worker/service_worker_registration.h"
 #include "content/browser/service_worker/service_worker_url_request_job.h"
 #include "content/browser/service_worker/service_worker_utils.h"
 #include "content/common/resource_request_body.h"
 #include "content/common/service_worker/service_worker_types.h"
 #include "net/base/load_flags.h"
 #include "net/base/net_util.h"
@@ skipping 82 matching lines @@
     return;
   }
   job_->GetExtraResponseInfo(was_fetched_via_service_worker,
                              original_url_via_service_worker);
 }
 
 void ServiceWorkerControlleeRequestHandler::PrepareForMainResource(
     const GURL& url) {
   DCHECK(job_.get());
   DCHECK(context_);
+  TRACE_EVENT_ASYNC_BEGIN1(
+      "ServiceWorker",
+      "ServiceWorkerControlleeRequestHandler::PrepareForMainResource",
+      job_.get(),
+      "URL", url.spec());
   // The corresponding provider_host may already have associated a registration
   // in redirect case, unassociate it now.
   provider_host_->UnassociateRegistration();
 
   GURL stripped_url = net::SimplifyUrlForRequest(url);
   provider_host_->SetDocumentUrl(stripped_url);
   context_->storage()->FindRegistrationForDocument(
       stripped_url,
       base::Bind(&self::DidLookupRegistrationForMainResource,
                  weak_factory_.GetWeakPtr()));
 }
 
 void
 ServiceWorkerControlleeRequestHandler::DidLookupRegistrationForMainResource(
     ServiceWorkerStatusCode status,
     const scoped_refptr<ServiceWorkerRegistration>& registration) {
   DCHECK(job_.get());
   if (status != SERVICE_WORKER_OK) {
     job_->FallbackToNetwork();
+    TRACE_EVENT_ASYNC_END1(
+        "ServiceWorker",
+        "ServiceWorkerControlleeRequestHandler::PrepareForMainResource",
+        job_.get(),
+        "Status", status);
     return;
   }
   DCHECK(registration.get());
 
   ServiceWorkerMetrics::CountControlledPageLoad();
 
   // Initiate activation of a waiting version.
   // Usually a register job initiates activation but that
   // doesn't happen if the browser exits prior to activation
   // having occurred. This check handles that case.
   if (registration->waiting_version())
     registration->ActivateWaitingVersionWhenReady();
 
   scoped_refptr<ServiceWorkerVersion> active_version =
       registration->active_version();
 
   // Wait until it's activated before firing fetch events.
   if (active_version.get() &&
       active_version->status() == ServiceWorkerVersion::ACTIVATING) {
     registration->active_version()->RegisterStatusChangeCallback(
         base::Bind(&self::OnVersionStatusChanged,
                    weak_factory_.GetWeakPtr(),
                    registration,
                    active_version));
+    TRACE_EVENT_ASYNC_END2(
+        "ServiceWorker",
+        "ServiceWorkerControlleeRequestHandler::PrepareForMainResource",
+        job_.get(),
+        "Status", status,
+        "Info", "Wait until finished SW activation");
     return;
   }
 
   if (!active_version.get() ||
       active_version->status() != ServiceWorkerVersion::ACTIVATED) {
     job_->FallbackToNetwork();
+    TRACE_EVENT_ASYNC_END2(
+        "ServiceWorker",
+        "ServiceWorkerControlleeRequestHandler::PrepareForMainResource",
+        job_.get(),
+        "Status", status,
+        "Info",
+        "ServiceWorkerVersion is not available, so falling back to network");
     return;
   }
 
   provider_host_->AssociateRegistration(registration.get());
   job_->ForwardToServiceWorker();
+  TRACE_EVENT_ASYNC_END2(
+      "ServiceWorker",
+      "ServiceWorkerControlleeRequestHandler::PrepareForMainResource",
+      job_.get(),
+      "Status", status,
+      "Info",
+      "Forwarded to the ServiceWorker");
 }
 
 void ServiceWorkerControlleeRequestHandler::OnVersionStatusChanged(
     ServiceWorkerRegistration* registration,
     ServiceWorkerVersion* version) {
   if (version != registration->active_version() ||
       version->status() != ServiceWorkerVersion::ACTIVATED) {
     job_->FallbackToNetwork();
     return;
   }
 
   provider_host_->AssociateRegistration(registration);
   job_->ForwardToServiceWorker();
 }
 
 void ServiceWorkerControlleeRequestHandler::PrepareForSubResource() {
   DCHECK(job_.get());
   DCHECK(context_);
   DCHECK(provider_host_->active_version());
   job_->ForwardToServiceWorker();
 }
 
 }  // namespace content