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

chrome/browser/download/chrome_download_manager_delegate.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_DOWNLOAD_CHROME_DOWNLOAD_MANAGER_DELEGATE_H_
 #define CHROME_BROWSER_DOWNLOAD_CHROME_DOWNLOAD_MANAGER_DELEGATE_H_
 #pragma once
 
 #include "base/compiler_specific.h"
 #include "base/hash_tables.h"
@@ skipping 46 matching lines @@
   virtual bool OverrideIntermediatePath(DownloadItem* item,
                                         FilePath* intermediate_path) OVERRIDE;
   virtual TabContents* GetAlternativeTabContentsToNotifyForDownload() OVERRIDE;
   virtual bool ShouldOpenFileBasedOnExtension(const FilePath& path) OVERRIDE;
   virtual bool ShouldOpenDownload(DownloadItem* item) OVERRIDE;
   virtual bool ShouldCompleteDownload(DownloadItem* item) OVERRIDE;
   virtual bool GenerateFileHash() OVERRIDE;
   virtual void OnResponseCompleted(DownloadItem* item,
                                    const std::string& hash) OVERRIDE;
   virtual void AddItemToPersistentStore(DownloadItem* item) OVERRIDE;
+  virtual void MarkDownloadOpened(int64 db_handle) OVERRIDE;
   virtual void UpdateItemInPersistentStore(DownloadItem* item) OVERRIDE;
   virtual void UpdatePathForItemInPersistentStore(
       DownloadItem* item,
       const FilePath& new_path) OVERRIDE;
   virtual void RemoveItemFromPersistentStore(DownloadItem* item) OVERRIDE;
   virtual void RemoveItemsFromPersistentStoreBetween(
       const base::Time remove_begin,
       const base::Time remove_end) OVERRIDE;
   virtual void GetSaveDir(TabContents* tab_contents,
                           FilePath* website_save_dir,
@@ skipping 64 matching lines @@
   // Maps from pending extension installations to DownloadItem IDs.
   typedef base::hash_map<CrxInstaller*, int> CrxInstallerMap;
   CrxInstallerMap crx_installers_;
 
   NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeDownloadManagerDelegate);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_CHROME_DOWNLOAD_MANAGER_DELEGATE_H_