Revert 102126 - Make cancel remove cancelled download from active queues at time of cancel.

content/browser/download/download_item.h

 // Copyright (c) 2011 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.
 //
 // Each download is represented by a DownloadItem, and all DownloadItems
 // are owned by the DownloadManager which maintains a global list of all
 // downloads. DownloadItems are created when a user initiates a download,
 // and exist for the duration of the browser life time.
 //
 // Download observers:
@@ skipping 139 matching lines @@
 
   // Show the download via the OS shell.
   void ShowDownloadInShell();
 
   // Called when the user has validated the download of a dangerous file.
   void DangerousDownloadValidated();
 
   // Received a new chunk of data
   void Update(int64 bytes_so_far);
 
-  // Cancel the download operation.  This may be called at any time; if
-  // it is called before all download attributes have been finalized and
-  // the download entered into the history, it will remove the download from
-  // the system.
-  void Cancel();
+  // Cancel the download operation. We need to distinguish between cancels at
+  // exit (DownloadManager destructor) from user interface initiated cancels
+  // because at exit, the history system may not exist, and any updates to it
+  // require AddRef'ing the DownloadManager in the destructor which results in
+  // a DCHECK failure. Set 'update_history' to false when canceling from at
+  // exit to prevent this crash. This may result in a difference between the
+  // downloaded file's size on disk, and what the history system's last record
+  // of it is. At worst, we'll end up re-downloading a small portion of the file
+  // when resuming a download (assuming the server supports byte ranges).
+  void Cancel(bool update_history);
 
   // Called by external code (SavePackage) using the DownloadItem interface
   // to display progress when the DownloadItem should be considered complete.
   void MarkAsComplete();
 
   // Called by the delegate after it delayed completing the download in
   // DownloadManagerDelegate::ShouldCompleteDownload.
   void CompleteDelayedDownload();
 
   // Called when all data has been saved. Only has display effects.
   void OnAllDataSaved(int64 size);
 
   // Called when the downloaded file is removed.
   void OnDownloadedFileRemoved();
 
-  // Download operation had an error; call to interrupt the processing.
-  // Note that if the download attributes haven't yet been finalized and
-  // the download entered into the history (which implies that it hasn't
-  // yet been made visible in the UI), this call will remove the
-  // download from the system.
-  // |size| is the amount of data received so far, and |net_error| is the
-  // error code that the operation received.
-  void Interrupt(int64 size, net::Error net_error);
+  // Download operation had an error.
+  // |size| is the amount of data received at interruption.
+  // |error| is the network error code that the operation received.
+  void Interrupted(int64 size, net::Error error);
 
   // Deletes the file from disk and removes the download from the views and
   // history.  |user| should be true if this is the result of the user clicking
   // the discard button, and false if it is being deleted for other reasons like
   // browser shutdown.
   void Delete(DeleteReason reason);
 
   // Removes the download from the views and history.
   void Remove();
 
@@ skipping 151 matching lines @@
   void UpdateSize(int64 size);
 
   // Called when the entire download operation (including renaming etc)
   // is completed.
   void Completed();
 
   // Start/stop sending periodic updates to our observers
   void StartProgressTimer();
   void StopProgressTimer();
 
-  // Does the actual work of transition state; all state
-  // transitions should go through this.
+  // Call to transition state; all state transitions should go through this.
   void TransitionTo(DownloadState new_state);
 
   // Called when safety_state_ should be recomputed from is_dangerous_file
   // and is_dangerous_url.
   void UpdateSafetyState();
 
   // Helper function to recompute |state_info_.target_name| when
   // it may have changed.  (If it's non-null it should be left alone,
   // otherwise updated from |full_path_|.)
   void UpdateTarget();
@@ skipping 108 matching lines @@
   // only.
   bool open_enabled_;
 
   // Did the delegate delay calling Complete on this download?
   bool delegate_delayed_complete_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadItem);
 };
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_H_