Show user data dialog earlier on Windows.

chrome/browser/user_data_dir_extractor.cc

Index: chrome/browser/user_data_dir_extractor.cc
diff --git a/chrome/browser/user_data_dir_extractor.cc b/chrome/browser/user_data_dir_extractor.cc
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+++ b/chrome/browser/user_data_dir_extractor.cc
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+// Copyright (c) 2013 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.
+
+#include "chrome/browser/user_data_dir_extractor.h"
+
+#include "base/files/file_path.h"
+#include "base/logging.h"
+#include "base/path_service.h"
+#include "chrome/common/chrome_paths.h"
+
+namespace chrome {
+
+base::FilePath GetUserDataDir(const content::MainFunctionParams& parameters) {
+  base::FilePath user_data_dir;
+
+  // Getting the user data dir can fail if the directory isn't creatable, for
+  // example: on Windows we bring up a dialog prompting the user to pick a
+  // different directory. However, ProcessSingleton needs a real user_data_dir
+  // on Mac/Linux, so it's better to fail here than fail mysteriously elsewhere.
+  CHECK(PathService::Get(chrome::DIR_USER_DATA, &user_data_dir))
+      << "Must be able to get user data directory!";
+  return user_data_dir;
+}
+
+}  // namespace chrome