When the download folder does not exist, change the download folder to a user's "Downloads"

chrome/browser/download/download_util.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.
 //
 // Download utilities.
 
 #ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_UTIL_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_UTIL_H_
 #pragma once
 
@@ skipping 32 matching lines @@
 
 namespace gfx {
 class Canvas;
 class Image;
 }
 
 namespace download_util {
 
 // Download temporary file creation --------------------------------------------
 
-// Return the default download directory.
-const FilePath& GetDefaultDownloadDirectory();
+// Chooses a writable directory from |website_save_dir|, |download_save_dir|
+// and |default_download_dir| in this order of priority.
+// If none of them is writable, creates |download_save_dir| and
+// chooses |download_save_dir|. The choosed directory is stored to |save_dir|.
+// Returns true if neither |website_save_dir| nor |download_save_dir|
+// is writable, which indicates the select file dialog should be displayed.
+bool ChooseSavableDirectory(const FilePath& website_save_dir,
+                            const FilePath& download_save_dir,
+                            const FilePath& default_download_dir,
+                            FilePath* save_dir);
 
-// Create a temporary file for a download in the user's default download
-// directory and return true if was successful in creating the file.
-bool CreateTemporaryFileForDownload(FilePath* path);
+// Returns the user's default "Downloads" folder provided by PathService.
+// This method returns the folder provided by PathService.
+FilePath GetDefaultDownloadDirectoryFromPathService();
 
 // Return true if the |download_path| is dangerous path.
 bool DownloadPathIsDangerous(const FilePath& download_path);
 
 // Generate a filename based on the response from the server.  Similar
 // in operation to net::GenerateFileName(), but uses a localized
 // default name.
 void GenerateFileNameFromRequest(const DownloadItem& download_item,
                                  FilePath* generated_name);
 
@@ skipping 189 matching lines @@
 // If |path| does not exist, 0 is returned.  If it fails to find such
 // a number, -1 is returned.
 int GetUniquePathNumberWithCrDownload(const FilePath& path);
 
 // Returns a .crdownload intermediate path for the |suggested_path|.
 FilePath GetCrDownloadPath(const FilePath& suggested_path);
 
 }  // namespace download_util
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_UTIL_H_