### Problem Description
I use ubuntu linux. my system language is Chinese, but the dialog button labels is English by default. I found the buttonLabel option from the API to set the label of the save or open button, but the label of the cancel button is not supported.

### Proposed Solution
Support customizing cancel button label in Open and Save dialogs

shell/browser/ui/file_dialog_gtk.cc
#include "shell/browser/ui/file_dialog.h"
#include <glib/gi18n.h>  
#include "base/callback.h"
#include "base/files/file_util.h"
#include "base/strings/string_util.h"
#include "chrome/browser/ui/libgtkui/gtk_util.h"
#include "shell/browser/native_window_views.h"
#include "shell/browser/unresponsive_suppressor.h"
#include "ui/base/glib/glib_signal.h"
#include "ui/views/widget/desktop_aura/x11_desktop_handler.h"
namespace file_dialog {
DialogSettings::DialogSettings() = default;
DialogSettings::DialogSettings(const DialogSettings&) = default;
DialogSettings::~DialogSettings() = default;
namespace {
static const int kPreviewWidth = 256;
static const int kPreviewHeight = 512;
gboolean FileFilterCaseInsensitive(const GtkFileFilterInfo* file_info,
                                   std::string* file_extension) {
  
  if (*file_extension == ".*")
    return true;
  return base::EndsWith(file_info->filename, *file_extension,
                        base::CompareCase::INSENSITIVE_ASCII);
}
void OnFileFilterDataDestroyed(std::string* file_extension) {
  delete file_extension;
}
class FileChooserDialog {