Show user data dialog earlier on Windows.

chrome/browser/ui/user_data_dir_dialog.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_UI_USER_DATA_DIR_DIALOG_H_
 #define CHROME_BROWSER_UI_USER_DATA_DIR_DIALOG_H_
 
+#include "base/callback.h"
+
 namespace base {
 class FilePath;
 }
 
 namespace chrome {
 
 // Shows a user data directory picker dialog. The method blocks while the dialog
 // is showing. If the user picks a directory, this method returns the chosen
 // directory. |user_data_dir| is the value of the directory we were not able to
 // use.
 base::FilePath ShowUserDataDirDialog(const base::FilePath& user_data_dir);
 
+// Tests can call this to install a custom callback to be called instead of
+// actually showing the dialog when ShowUserDataDirDialog() is invoked.
+void InstallCustomShowUserDataDirDialogCallbackForTest(
+    const base::Closure& callback);
+
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_UI_USER_DATA_DIR_DIALOG_H_