Handle the case where IAttachmentExecute::Save() deletes a downloaded file.

content/browser/download/download_stats.h

 // Copyright (c) 2012 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.
 //
 // Holds helpers for gathering UMA stats about downloads.
 
 #ifndef CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_STATS_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_STATS_H_
 
 #include <string>
@@ skipping 45 matching lines @@
   // Counts interruptions that happened at the end of the download.
   INTERRUPTED_AT_END_COUNT,
 
   // Counts errors due to writes to BaseFiles that have been detached already.
   // This can happen when saving web pages as complete packages. It happens
   // when we get messages to append data to files that have already finished and
   // been detached, but haven't yet been removed from the list of files in
   // progress.
   APPEND_TO_DETACHED_FILE_COUNT,
 
+  // Counts the number of instances where the downloaded file is missing after a
+  // successful invocation of win_util::ScanAndSaveDownloadedFile().
+  FILE_MISSING_AFTER_SUCCESSFUL_SCAN_COUNT,
+
   DOWNLOAD_COUNT_TYPES_LAST_ENTRY
 };
 
 enum DownloadSource {
   // The download was initiated when the SavePackage system rejected
   // a Save Page As ... by returning false from
   // SavePackage::IsSaveableContents().
   INITIATED_BY_SAVE_PACKAGE_ON_NON_HTML = 0,
 
   // The download was initiated by a drag and drop from a drag-and-drop
@@ skipping 92 matching lines @@
   SAVE_PACKAGE_WRITE_TO_FAILED,
 
   SAVE_PACKAGE_LAST_ENTRY
 };
 
 void RecordSavePackageEvent(SavePackageEvent event);
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_STATS_H_