Enable "Hide Extension" option when "Save Link As" on the Mac

ui/shell_dialogs/select_file_dialog_mac.mm

Index: ui/shell_dialogs/select_file_dialog_mac.mm
diff --git a/ui/shell_dialogs/select_file_dialog_mac.mm b/ui/shell_dialogs/select_file_dialog_mac.mm
index 9a4a5fd386792122f0c7d6a3ad1832d97f5f26a9..6ba1f0d1ce74045cdb9b7275c553e1961d57293e 100644
--- a/ui/shell_dialogs/select_file_dialog_mac.mm
+++ b/ui/shell_dialogs/select_file_dialog_mac.mm
@@ -21,6 +21,7 @@
 #include "base/threading/thread_restrictions.h"
 #import "ui/base/cocoa/nib_loading.h"
 #include "ui/base/l10n/l10n_util_mac.h"
+#include "ui/shell_dialogs/selected_file_info.h"
 #include "ui/strings/grit/ui_strings.h"
 
 namespace {
@@ -150,7 +151,11 @@ void SelectFileDialogImpl::FileWasSelected(
     if (is_multi) {
       listener_->MultiFilesSelected(files, params);
     } else {
-      listener_->FileSelected(files[0], index, params);
+      ui::SelectedFileInfo file(files[0], base::FilePath());
+      if ([dialog isExtensionHidden]) {
+        file.SetHideFileExtension(true);
+      }
+      listener_->FileSelectedWithExtraInfo(file, index, params);
     }
   }
 }