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 always returns the folder provided by PathService
+// even if the folder is being overridden. We should use
+// DownloadPrefs::GetDefaultDownloadDirectory() instead unless we really
+// want the folder directly provided by PathService.
+FilePath GetDefaultDownloadDirectoryFromPathService();
 
 // Return true if the |download_path| is dangerous path.
 bool DownloadPathIsDangerous(const FilePath& download_path);
 
 // Create an extension based on the file name and mime type.
 void GenerateExtension(const FilePath& file_name,
                        const std::string& mime_type,
                        FilePath::StringType* generated_extension);
 
 // Create a file name based on the response from the server.
@@ skipping 212 matching lines @@
 // Erases all downloaded files with the specified path and name prefix.
 // Used by download UI tests to clean up the download directory.
 void EraseUniqueDownloadFiles(const FilePath& path_prefix);
 
 // 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_