Add new UMA stats to get a handle on Downloads UI Usage

chrome/browser/history/history.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.
 
 #ifndef CHROME_BROWSER_HISTORY_HISTORY_H_
 #define CHROME_BROWSER_HISTORY_HISTORY_H_
 #pragma once
 
 #include <set>
 #include <vector>
@@ skipping 431 matching lines @@
   Handle QueryDownloads(CancelableRequestConsumerBase* consumer,
                         DownloadQueryCallback* callback);
 
   // Begins a request to clean up entries that has been corrupted (because of
   // the crash, for example).
   void CleanUpInProgressEntries();
 
   // Called to update the history service about the current state of a download.
   // This is a 'fire and forget' query, so just pass the relevant state info to
   // the database with no need for a callback.
-  void UpdateDownload(int64 received_bytes, int32 state, int64 db_handle);
+  void UpdateDownload(history::DownloadItemData data);
 
   // Called to update the history service about the path of a download.
   // This is a 'fire and forget' query.
   void UpdateDownloadPath(const FilePath& path, int64 db_handle);
 
   // Permanently remove a download from the history system. This is a 'fire and
   // forget' operation.
   void RemoveDownload(int64 db_handle);
 
   // Permanently removes all completed download from the history system within
@@ skipping 416 matching lines @@
   BookmarkService* bookmark_service_;
   bool no_db_;
 
   // True if needs top site migration.
   bool needs_top_sites_migration_;
 
   DISALLOW_COPY_AND_ASSIGN(HistoryService);
 };
 
 #endif  // CHROME_BROWSER_HISTORY_HISTORY_H_