Make Foreign Fetch an origin trial.

content/browser/service_worker/foreign_fetch_request_handler.h

 // Copyright 2015 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_FOREIGN_FETCH_REQUEST_HANDLER_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_FOREIGN_FETCH_REQUEST_HANDLER_H_
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/supports_user_data.h"
@@ skipping 28 matching lines @@
 struct ResourceResponseInfo;
 
 // Class for routing network requests to ServiceWorkers for foreign fetch
 // events. Created one per URLRequest and attached to each request.
 // TODO(mek): Does this need something similar to ServiceWorkerRequestHandler's
 // GetExtraResponseInfo method?
 class CONTENT_EXPORT ForeignFetchRequestHandler
     : public base::SupportsUserData::Data,
       public ServiceWorkerURLRequestJob::Delegate {
  public:
+  // Returns true if Foreign Fetch is enabled. Foreign Fetch is considered to be
+  // enabled if an OriginTrialPolicy exists, and that policy doesn't disable the
+  // feature. When the policy does disable the feature, that can be overridden
+  // with the experimental web platform features command line flag.
+  static bool IsForeignFetchEnabled();
+
   // Attaches a newly created handler if the given |request| needs to
   // be handled by a foreign fetch handling ServiceWorker.
   static void InitializeHandler(
       net::URLRequest* request,
       ServiceWorkerContextWrapper* context_wrapper,
       storage::BlobStorageContext* blob_storage_context,
       int process_id,
       int provider_id,
       SkipServiceWorker skip_service_worker,
       FetchRequestMode request_mode,
@@ skipping 66 matching lines @@
   bool use_network_ = false;
 
   base::WeakPtrFactory<ForeignFetchRequestHandler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ForeignFetchRequestHandler);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_FOREIGN_FETCH_REQUEST_HANDLER_H_