Race condition in component_updater::BackgroundDowloader (follow up)

chrome/browser/component_updater/background_downloader_win.h

 // Copyright 2013 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_COMPONENT_UPDATER_BACKGROUND_DOWNLOADER_WIN_H_
 #define CHROME_BROWSER_COMPONENT_UPDATER_BACKGROUND_DOWNLOADER_WIN_H_
 
 #include "chrome/browser/component_updater/crx_downloader.h"
 
 #include <windows.h>
@@ skipping 18 matching lines @@
                        scoped_refptr<base::SequencedTaskRunner> task_runner,
                        const DownloadCallback& download_callback);
   virtual ~BackgroundDownloader();
 
  private:
   // Overrides for CrxDownloader.
   virtual void DoStartDownload(const GURL& url) OVERRIDE;
 
   // Called asynchronously on the FILE thread at different stages during
   // the download. |OnDownloading| can be called multiple times.
+  // |EndDownload| switches the execution flow from the FILE to the UI thread.
+  // Accessing any data members of this object on the FILE thread after
+  // calling |EndDownload| is unsafe.
   void BeginDownload(const GURL& url);
   void OnDownloading();
   void EndDownload(HRESULT hr);
 
   // Handles the job state transitions to a final state.
   void OnStateTransferred();
   void OnStateError();
   void OnStateCancelled();
   void OnStateAcknowledged();
 
@@ skipping 31 matching lines @@
 
   bool is_completed_;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundDownloader);
 };
 
 }  // namespace component_updater
 
 #endif  // CHROME_BROWSER_COMPONENT_UPDATER_BACKGROUND_DOWNLOADER_WIN_H_