DialogDelegate: allow platforms to prevent Cancel being default

ui/views/window/dialog_delegate.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 "ui/views/window/dialog_delegate.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "build/build_config.h"
 #include "ui/accessibility/ax_view_state.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/gfx/color_palette.h"
 #include "ui/strings/grit/ui_strings.h"
 #include "ui/views/bubble/bubble_border.h"
 #include "ui/views/bubble/bubble_frame_view.h"
 #include "ui/views/controls/button/label_button.h"
 #include "ui/views/layout/layout_constants.h"
+#include "ui/views/style/platform_style.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_observer.h"
 #include "ui/views/window/dialog_client_view.h"
 
 #if defined(OS_WIN)
 #include "ui/base/win/shell.h"
 #endif
 
 namespace views {
 
@@ skipping 83 matching lines @@
   if ((buttons & ui::DIALOG_BUTTON_CANCEL) ||
       (buttons == ui::DIALOG_BUTTON_NONE)) {
     return Cancel();
   }
   return Accept();
 }
 
 void DialogDelegate::UpdateButton(LabelButton* button, ui::DialogButton type) {
   button->SetText(GetDialogButtonLabel(type));
   button->SetEnabled(IsDialogButtonEnabled(type));
-  button->SetIsDefault(type == GetDefaultDialogButton());
+  bool is_default = type == GetDefaultDialogButton();
+  if (!PlatformStyle::kDialogDefaultButtonCanBeCancel &&
+      type == ui::DIALOG_BUTTON_CANCEL) {
+    is_default = false;
+  }
+  button->SetIsDefault(is_default);
 }
 
 int DialogDelegate::GetDialogButtons() const {
   return ui::DIALOG_BUTTON_OK | ui::DIALOG_BUTTON_CANCEL;
 }
 
 int DialogDelegate::GetDefaultDialogButton() const {
   if (GetDialogButtons() & ui::DIALOG_BUTTON_OK)
     return ui::DIALOG_BUTTON_OK;
   if (GetDialogButtons() & ui::DIALOG_BUTTON_CANCEL)
@@ skipping 120 matching lines @@
   state->role = ui::AX_ROLE_DIALOG;
 }
 
 void DialogDelegateView::ViewHierarchyChanged(
     const ViewHierarchyChangedDetails& details) {
   if (details.is_add && details.child == this && GetWidget())
     NotifyAccessibilityEvent(ui::AX_EVENT_ALERT, true);
 }
 
 }  // namespace views