Enable ServiceWorkerNavigationPreload by default

content/browser/service_worker/service_worker_version.h

 // 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.
 
 #ifndef CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_VERSION_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_VERSION_H_
 
 #include <stdint.h>
 
 #include <functional>
@@ skipping 84 matching lines @@
                          // timed out.
   };
 
   // Whether the version has fetch handlers or not.
   enum class FetchHandlerExistence {
     UNKNOWN,  // This version is a new version and not installed yet.
     EXISTS,
     DOES_NOT_EXIST,
   };
 
-  // Navigation Preload support status of the service worker.
-  enum class NavigationPreloadSupportStatus {
-    SUPPORTED,
-    NOT_SUPPORTED_FIELD_TRIAL_STOPPED,
-    NOT_SUPPORTED_DISABLED_BY_COMMAND_LINE,
-    NOT_SUPPORTED_NO_VALID_ORIGIN_TRIAL_TOKEN,
-  };
-
   class Listener {
    public:
     virtual void OnRunningStateChanged(ServiceWorkerVersion* version) {}
     virtual void OnVersionStateChanged(ServiceWorkerVersion* version) {}
     virtual void OnDevToolsRoutingIdChanged(ServiceWorkerVersion* version) {}
     virtual void OnMainScriptHttpResponseInfoSet(
         ServiceWorkerVersion* version) {}
     virtual void OnErrorReported(ServiceWorkerVersion* version,
                                  const base::string16& error_message,
                                  int line_number,
@@ skipping 279 matching lines @@
   size_t GetExternalRequestCountForTest() const {
     return external_request_uuid_to_request_id_.size();
   }
 
   // Returns the amount of time left until the request with the latest
   // expiration time expires.
   base::TimeDelta remaining_timeout() const {
     return max_request_expiration_time_ - tick_clock_->NowTicks();
   }
 
-  // Returns the Navigation Preload support status of the service worker.
-  //  - Origin Trial: Have an effective token.
-  //                                 Command line
-  //                             Default  Enable  Disabled
-  //                   Default      A       A        B2
-  //      Field trial  Enabled      A       A        B2
-  //                   Disabled     B1      A        B2
-  //
-  //  - Origin Trial: No token.
-  //                                 Command line
-  //                             Default  Enable  Disabled
-  //                   Default      C       A        C
-  //      Field trial  Enabled      C       A        C
-  //                   Disabled     C       A        C
-  //
-  //   * A  = SUPPORTED
-  //     B1 = NOT_SUPPORTED_FIELD_TRIAL_STOPPED
-  //     B2 = NOT_SUPPORTED_DISABLED_BY_COMMAND_LINE
-  //     C  = NOT_SUPPORTED_NO_VALID_ORIGIN_TRIAL_TOKEN
-  //
-  // There are three types of behaviors:
-  //  - A: Navigation Preload related methods and attributes are available in JS
-  //       and work correctly.
-  //  - B: Navigation Preload related methods and attributes are available in
-  //       JS. But NavigationPreloadManager's enable, disable and setHeaderValue
-  //       methods always return a rejected promise. And FetchEvent's
-  //       preloadResponse attribute returns a promise which always resolve with
-  //       undefined.
-  //  - C: Navigation Preload related methods and attributes are not available
-  //       in JS.
-  // This method returns SUPPORTED only for A case.
-  // blink::OriginTrials::serviceWorkerNavigationPreloadEnabled() returns true
-  // for both A and B case. So the methods and attributes are available in JS.
-  NavigationPreloadSupportStatus GetNavigationPreloadSupportStatus() const;
-
   void CountFeature(uint32_t feature);
   void set_used_features(const std::set<uint32_t>& used_features) {
     used_features_ = used_features;
   }
   const std::set<uint32_t>& used_features() const { return used_features_; }
 
  private:
   friend class base::RefCounted<ServiceWorkerVersion>;
   friend class ServiceWorkerMetrics;
   friend class ServiceWorkerReadFromCacheJobTest;
@@ skipping 421 matching lines @@
 
   // At this point |this| can have been deleted, so don't do anything other
   // than returning.
 
   return true;
 }
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_VERSION_H_