Introduce chrome://flags/#network-prediction-options-for-service-worker

chrome/browser/net/predictor_tab_helper.cc

 // Copyright 2013 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 "chrome/browser/net/predictor_tab_helper.h"
 
 #include "base/feature_list.h"
+#include "base/trace_event/trace_event.h"
+#include "chrome/browser/net/prediction_options.h"
 #include "chrome/browser/net/predictor.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/url_constants.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/browser/navigation_handle.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/service_worker_context.h"
+#include "content/public/browser/storage_partition.h"
 #include "content/public/common/browser_side_navigation_policy.h"
+#include "content/public/common/content_features.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
 #endif  // defined(OS_CHROMEOS)
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(chrome_browser_net::PredictorTabHelper);
 
 namespace chrome_browser_net {
 
 namespace {
 
 // Triggers the preconnector on renderer-initiated navigations. This captures
 // more navigations.
 const base::Feature kPreconnectMore{"PreconnectMore",
                                     base::FEATURE_DISABLED_BY_DEFAULT};
 
 }  // namespace
 
 PredictorTabHelper::PredictorTabHelper(content::WebContents* web_contents)
     : content::WebContentsObserver(web_contents),
-      predicted_from_pending_entry_(false) {
-}
+      predicted_from_pending_entry_(false),
+      weak_factory_(this) {}
 
 PredictorTabHelper::~PredictorTabHelper() {
 }
 
 void PredictorTabHelper::DidStartNavigation(
     content::NavigationHandle* navigation_handle) {
+  TRACE_EVENT1("net", "PredictorTabHelper::DidStartNavigation", "url",
+               navigation_handle->GetURL().spec());
   if (!base::FeatureList::IsEnabled(kPreconnectMore) &&
       (!content::IsBrowserSideNavigationEnabled() ||
        navigation_handle->IsRendererInitiated()))
     return;
   // Subframe navigations are handled in WitnessURLRequest.
   if (!navigation_handle->IsInMainFrame())
     return;
   if (predicted_from_pending_entry_) {
     predicted_from_pending_entry_ = false;
     return;
   }
-  PreconnectUrl(navigation_handle->GetURL());
+  HandleNavigation(navigation_handle->GetURL());
 }
 
 void PredictorTabHelper::DidStartNavigationToPendingEntry(
     const GURL& url,
     content::ReloadType reload_type) {
+  TRACE_EVENT1("net", "PredictorTabHelper::DidStartNavigationToPendingEntry",
+               "url", url.spec());
   // This method isn't needed with PlzNavigate (see comment in header for
   // predicted_from_pending_entry_)
   if (content::IsBrowserSideNavigationEnabled())
     return;
 
   // The standard way to preconnect based on navigation.
-  PreconnectUrl(url);
+  HandleNavigation(url);
   predicted_from_pending_entry_ = true;
 }
 
 void PredictorTabHelper::DocumentOnLoadCompletedInMainFrame() {
   Profile* profile =
       Profile::FromBrowserContext(web_contents()->GetBrowserContext());
   Predictor* predictor = profile->GetNetworkPredictor();
 #if defined(OS_CHROMEOS)
   if (chromeos::ProfileHelper::IsSigninProfile(profile))
     return;
 #endif
   if (predictor)
     predictor->SaveStateForNextStartup();
 }
 
-void PredictorTabHelper::PreconnectUrl(const GURL& url) {
+void PredictorTabHelper::HandleNavigation(const GURL& url) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  TRACE_EVENT1("net", "PredictorTabHelper::HandleNavigation", "url",
+               url.spec());
+  if (!url.SchemeIsHTTPOrHTTPS())
+    return;
+  content::RenderProcessHost* host = web_contents()->GetRenderProcessHost();
+  NetworkPredictionOptionsForServiceWorker options =
+      GetNetworkPredictionOptionsForServiceWorker();
+  if (!host ||
+      options == NetworkPredictionOptionsForServiceWorker::PRECONNECT_ONLY) {
+    PreconnectUrlWithPredictor(url);
+    return;
+  }
+
+  host->GetStoragePartition()
+      ->GetServiceWorkerContext()
+      ->StartServiceWorkerForNavigationPreconnect(
+          url, host,
+          base::Bind(
+              &PredictorTabHelper::DidStartServiceWorkerForNavigaionPreconnect,
+              weak_factory_.GetWeakPtr(), url));
+  if (options == NetworkPredictionOptionsForServiceWorker::
+                     START_SERVICE_WORKER_AND_PRECONNECT) {
+    PreconnectUrlWithPredictor(url);
+  }
+}
+
+void PredictorTabHelper::DidStartServiceWorkerForNavigaionPreconnect(

[falken, 2017/06/01 06:54:17]

Navigation

[horo, 2017/06/01 11:15:06]

Done.

+    const GURL& url,
+    bool success) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  TRACE_EVENT1("net", "PredictorTabHelper::DidStartServiceWorkerForPreconnect",
+               "success", success);
+  NetworkPredictionOptionsForServiceWorker options =
+      GetNetworkPredictionOptionsForServiceWorker();
+  if ((!success && options != NetworkPredictionOptionsForServiceWorker::
+                                  START_SERVICE_WORKER_AND_PRECONNECT) ||
+      options == NetworkPredictionOptionsForServiceWorker::
+                     START_SERVICE_WORKER_AND_DEFER_PRECONNECT) {

[falken, 2017/06/01 06:54:17]

I feel a switch would be more readable here, since it we're already mentioning 2
of 4 of the cases, and more robust to changes to the enum later.

[horo, 2017/06/01 11:15:06]

Done.

+    PreconnectUrlWithPredictor(url);
+  }
+}
+
+void PredictorTabHelper::PreconnectUrlWithPredictor(const GURL& url) {

[falken, 2017/06/01 06:54:17]

I'm wondering why did the name change to WithPredictor? It seems PreconnectUrl
was always done by (with?) the predictor.

[horo, 2017/06/01 11:15:06]

Done.

   Profile* profile =
       Profile::FromBrowserContext(web_contents()->GetBrowserContext());
   Predictor* predictor(profile->GetNetworkPredictor());
-  if (predictor && url.SchemeIsHTTPOrHTTPS())
-    predictor->PreconnectUrlAndSubresources(url, GURL());
+  if (!predictor)
+    return;
+  predictor->PreconnectUrlAndSubresources(url, GURL());
 }
 
 }  // namespace chrome_browser_net