[Offline pages]: Implement background loader to save on last retry, and record last retry success U…

components/offline_pages/core/background/offliner.h

 // Copyright 2016 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 COMPONENTS_OFFLINE_PAGES_CORE_BACKGROUND_OFFLINER_H_
 #define COMPONENTS_OFFLINE_PAGES_CORE_BACKGROUND_OFFLINER_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 37 matching lines @@
     // processing another request at this time.
     LOADING_FAILED_NO_NEXT = 11,
     // The RequestCoordinator tried to start loading the request but the
     // loading request was not accepted.
     LOADING_NOT_ACCEPTED = 12,
     // The RequestCoordinator did not start loading the request because
     // updating the status in the request queue failed.
     QUEUE_UPDATE_FAILED = 13,
     // Scheduler canceled processing of requests.
     BACKGROUND_SCHEDULER_CANCELED = 14,
+    // We saved a snapshot on the last retry, after timeout.
+    SAVED_ON_LAST_RETRY = 15,
     // NOTE: insert new values above this line and update histogram enum too.
     STATUS_COUNT
   };
 
   // Reports the load progress of a request.
   typedef base::Callback<void(const SavePageRequest&, int64_t received_bytes)>
       ProgressCallback;
   // Reports the completion status of a request.
   // TODO(dougarnett): consider passing back a request id instead of request.
   typedef base::Callback<void(const SavePageRequest&, RequestStatus)>
@@ skipping 21 matching lines @@
   // Handles timeout scenario. Returns true if lowbar is met and try to do a
   // snapshot of the current webcontents.
   virtual bool HandleTimeout(const SavePageRequest& request) = 0;
 
   // TODO(dougarnett): add policy support methods.
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_CORE_BACKGROUND_OFFLINER_H_