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

chrome/browser/net/prediction_options.h

 // 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.
 
 #ifndef CHROME_BROWSER_NET_PREDICTION_OPTIONS_H_
 #define CHROME_BROWSER_NET_PREDICTION_OPTIONS_H_
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
@@ skipping 14 matching lines @@
   NETWORK_PREDICTION_NEVER,
   NETWORK_PREDICTION_DEFAULT = NETWORK_PREDICTION_WIFI_ONLY,
 };
 
 enum class NetworkPredictionStatus {
   ENABLED,
   DISABLED_ALWAYS,
   DISABLED_DUE_TO_NETWORK,
 };
 
+enum class NetworkPredictionOptionsForServiceWorker {
+  PRECONNECT_ONLY,
+  START_SERVICE_WORKER_AND_PRECONNECT,
+  START_SERVICE_WORKER_AND_DEFER_PRECONNECT,
+  START_SERVICE_WORKER_ONLY
+};
+
+extern const char kPreconnectOnly[];
+extern const char kStartServiceWorkerAndPreconnect[];
+extern const char kStartServiceWorkerAndDeferPreconnect[];
+extern const char kStartServiceWorkerOnly[];
+
 void RegisterPredictionOptionsProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry);
 
 // The following two global functions determine whether prefetching
 // and prerendering are enabled, based on preferences and network type.
 
 // To be executed on the IO thread only.
 NetworkPredictionStatus CanPrefetchAndPrerenderIO(
     ProfileIOData* profile_io_data);
 
 // To be executed on the UI thread only.
 NetworkPredictionStatus CanPrefetchAndPrerenderUI(PrefService* prefs);
 
 // The following two global functions determine whether TCP preconnect
 // and DNS preresolution are enabled, based on preferences.
 
 // To be executed on the IO thread only.
 bool CanPreresolveAndPreconnectIO(ProfileIOData* profile_io_data);
 
 // To be executed on the UI thread only.
 bool CanPreresolveAndPreconnectUI(PrefService* prefs);
 
+NetworkPredictionOptionsForServiceWorker
+GetNetworkPredictionOptionsForServiceWorker();
+
 }  // namespace chrome_browser_net
 
 #endif  // CHROME_BROWSER_NET_PREDICTION_OPTIONS_H_