[downloads] Move platform specific code out of DownloadTargetDeterminer.

chrome/browser/download/download_file_picker.h

Index: chrome/browser/download/download_file_picker.h
diff --git a/chrome/browser/download/download_file_picker.h b/chrome/browser/download/download_file_picker.h
index f925d0a6c19b661b29d20dc37674364433d66869..d507d282d1220a1d5c6d067799f5491de5049a77 100644
--- a/chrome/browser/download/download_file_picker.h
+++ b/chrome/browser/download/download_file_picker.h
@@ -7,6 +7,7 @@
 
 #include "base/callback.h"
 #include "base/macros.h"
+#include "chrome/browser/download/download_confirmation_result.h"
 #include "ui/shell_dialogs/select_file_dialog.h"
 
 namespace base {
@@ -28,7 +29,8 @@ class DownloadFilePicker : public ui::SelectFileDialog::Listener {
   //    selection, then this parameter will be the empty path. On Chrome OS,
   //    this path may contain virtual mount points if the user chose a virtual
   //    path (e.g. Google Drive).
-  typedef base::Callback<void(const base::FilePath& virtual_path)>
+  typedef base::Callback<void(DownloadConfirmationResult,
+                              const base::FilePath& virtual_path)>
       FileSelectedCallback;
 
   // Display a file picker dialog for |item|. The |suggested_path| will be used