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

base/path_service.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 BASE_PATH_SERVICE_H_
 #define BASE_PATH_SERVICE_H_
 #pragma once
 
 #include <string>
 
 #include "base/base_api.h"
 #include "base/base_paths.h"
 #include "build/build_config.h"
 
 class FilePath;
 
 // The path service is a global table mapping keys to file system paths.  It is
 // OK to use this service from multiple threads.
 //
 class BASE_API PathService {
  public:
   // Retrieves a path to a special directory or file and places it into the
-  // string pointed to by 'path'. If you ask for a directory it is guaranteed
+  // string pointed to by |path|. If you ask for a directory it is guaranteed
   // to NOT have a path separator at the end. For example, "c:\windows\temp"
   // Directories are also guaranteed to exist when this function succeeds.
   //
   // Returns true if the directory or file was successfully retrieved. On
-  // failure, 'path' will not be changed.
+  // failure, |path| will not be changed.
   static bool Get(int key, FilePath* path);
 
+  // Sets a path to a special directory or file. This overwrites the current
+  // path of the special directory or file. |path| may be a non-existent path.
+  static void Set(int key, const FilePath& path);

[Paweł Hajdan Jr., 2011/06/08 09:50:23]

Please remove all modifications to base/

[haraken1, 2011/06/09 10:16:56]

Done.

+
   // Overrides the path to a special directory or file.  This cannot be used to
   // change the value of DIR_CURRENT, but that should be obvious.  Also, if the
   // path specifies a directory that does not exist, the directory will be
   // created by this method.  This method returns true if successful.
   //
   // If the given path is relative, then it will be resolved against
   // DIR_CURRENT.
   //
   // WARNING: Consumers of PathService::Get may expect paths to be constant
   // over the lifetime of the app, so this method should be used with caution.
@@ skipping 14 matching lines @@
   static void RegisterProvider(ProviderFunc provider,
                                int key_start,
                                int key_end);
  private:
   static bool GetFromCache(int key, FilePath* path);
   static bool GetFromOverrides(int key, FilePath* path);
   static void AddToCache(int key, const FilePath& path);
 };
 
 #endif  // BASE_PATH_SERVICE_H_