[downloads] Move platform specific code out of DownloadTargetDeterminer.

chrome/browser/download/download_file_picker.cc

 // 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.
 
 #include "chrome/browser/download/download_file_picker.h"
 
 #include "base/metrics/histogram_macros.h"
 #include "chrome/browser/download/download_prefs.h"
 #include "chrome/browser/platform_util.h"
 #include "chrome/browser/ui/chrome_select_file_policy.h"
@@ skipping 78 matching lines @@
                                   owning_window,
                                   NULL);
 }
 
 DownloadFilePicker::~DownloadFilePicker() {
 }
 
 void DownloadFilePicker::OnFileSelected(const base::FilePath& path) {
   if (should_record_file_picker_result_)
     RecordFilePickerResult(suggested_path_, path);
-  file_selected_callback_.Run(path);
+  file_selected_callback_.Run(path.empty()
+                                  ? DownloadConfirmationResult::CANCELED
+                                  : DownloadConfirmationResult::CONFIRMED,
+                              path);
   delete this;
 }
 
 void DownloadFilePicker::FileSelected(const base::FilePath& path,
                                       int index,
                                       void* params) {
   OnFileSelected(path);
   // Deletes |this|
 }
 
 void DownloadFilePicker::FileSelectionCanceled(void* params) {
   OnFileSelected(base::FilePath());
   // Deletes |this|
 }
 
 // static
 void DownloadFilePicker::ShowFilePicker(DownloadItem* item,
                                         const base::FilePath& suggested_path,
                                         const FileSelectedCallback& callback) {
   new DownloadFilePicker(item, suggested_path, callback);
   // DownloadFilePicker deletes itself.
 }