Show or open downloaded items on the UI thread for Mac

chrome/browser/download/download_file.h

 // Copyright (c) 2006-2008 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.
 //
 // Objects that handle file operations for downloads, on the download thread.
 //
 // The DownloadFileManager owns a set of DownloadFile objects, each of which
 // represent one in progress download and performs the disk IO for that
 // download. The DownloadFileManager itself is a singleton object owned by the
 // ResourceDispatcherHost.
@@ skipping 183 matching lines @@
   void OnDownloadUrl(const GURL& url,
                      const GURL& referrer,
                      int render_process_host_id,
                      int render_view_id,
                      URLRequestContext* request_context);
 
   // Called on the UI thread to remove a download item or manager.
   void RemoveDownloadManager(DownloadManager* manager);
   void RemoveDownload(int id, DownloadManager* manager);
 
+#if !defined(OS_MACOSX)
+  // The open and show methods run on the file thread, which does not work on
+  // Mac OS X (which uses the UI thread for opens).
+
   // Handler for shell operations sent from the UI to the download thread.
   void OnShowDownloadInShell(const FilePath& full_path);
+
   // Handler to open or execute a downloaded file.
   void OnOpenDownloadInShell(const FilePath& full_path,
                              const GURL& url,
                              gfx::NativeView parent_window);
+#endif
 
   // The download manager has provided a final name for a download. Sent from
   // the UI thread and run on the download thread.
   void OnFinalDownloadName(int id, const FilePath& full_path,
                            DownloadManager* download_manager);
 
   // Timer notifications.
   void UpdateInProgressDownloads();
 
   MessageLoop* file_loop() const { return file_loop_; }
@@ skipping 55 matching lines @@
   // Used for progress updates on the UI thread, mapping download->id() to bytes
   // received so far. Written to by the file thread and read by the UI thread.
   typedef base::hash_map<int, int64> ProgressMap;
   ProgressMap ui_progress_;
   Lock progress_lock_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadFileManager);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_FILE_H_