Use the user's preferred downloads directory for creating the initial download file.

chrome/browser/download/chrome_download_manager_delegate.h

 // Copyright (c) 2012 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_DOWNLOAD_CHROME_DOWNLOAD_MANAGER_DELEGATE_H_
 #define CHROME_BROWSER_DOWNLOAD_CHROME_DOWNLOAD_MANAGER_DELEGATE_H_
 
 #include "base/compiler_specific.h"
 #include "base/hash_tables.h"
 #include "base/memory/ref_counted.h"
@@ skipping 68 matching lines @@
   virtual void UpdateItemInPersistentStore(
       content::DownloadItem* item) OVERRIDE;
   virtual void UpdatePathForItemInPersistentStore(
       content::DownloadItem* item,
       const FilePath& new_path) OVERRIDE;
   virtual void RemoveItemFromPersistentStore(
       content::DownloadItem* item) OVERRIDE;
   virtual void RemoveItemsFromPersistentStoreBetween(
       base::Time remove_begin,
       base::Time remove_end) OVERRIDE;
-  virtual void GetSaveDir(content::WebContents* web_contents,
+  virtual void GetSaveDir(content::BrowserContext* browser_context,
                           FilePath* website_save_dir,
                           FilePath* download_save_dir,
                           bool* skip_dir_check) OVERRIDE;
   virtual void ChooseSavePath(
       content::WebContents* web_contents,
       const FilePath& suggested_path,
       const FilePath::StringType& default_extension,
       bool can_save_as_complete,
       const content::SavePackagePathPickedCallback& callback) OVERRIDE;
 
@@ skipping 157 matching lines @@
 #endif
 
   // The directory most recently chosen by the user in response to a Save As
   // dialog for a regular download.
   FilePath last_download_path_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeDownloadManagerDelegate);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_CHROME_DOWNLOAD_MANAGER_DELEGATE_H_