Fix the Download Notifications for Offline Pages to indicate bytes loaded.

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 41 matching lines @@
     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,
     // 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)>
       CompletionCallback;
 
   Offliner() {}
   virtual ~Offliner() {}
 
   // Processes |request| to load and save an offline page.
-  // Returns whether the request was accepted or not. |callback| is guaranteed
-  // to be called if the request was accepted and |Cancel()| is not called.
+  // Returns whether the request was accepted or not. |completion_callback| is
+  // guaranteed to be called if the request was accepted and |Cancel()| is not
+  // called on it. |progress_callback| is invoked periodically to report the
+  // number of bytes received from the network (for UI purposes).
   virtual bool LoadAndSave(const SavePageRequest& request,
-                           const CompletionCallback& callback) = 0;
+                           const CompletionCallback& completion_callback,
+                           const ProgressCallback& progress_callback) = 0;
 
   // Clears the currently processing request, if any, and skips running its
   // CompletionCallback.
   virtual void Cancel() = 0;
 
   // 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_