BubbleFrameView: add padding if platform dislikes close buttons

ui/views/widget/widget_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/widget/widget_delegate.h"
 
 #include "base/strings/utf_string_conversions.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/views/view.h"
 #include "ui/views/views_delegate.h"
@@ skipping 61 matching lines @@
 
 base::string16 WidgetDelegate::GetWindowTitle() const {
   return base::string16();
 }
 
 bool WidgetDelegate::ShouldShowWindowTitle() const {
   return true;
 }
 
 bool WidgetDelegate::ShouldShowCloseButton() const {
-#if defined(OS_MACOSX)
-  return false;

[msw, 2016/07/28 19:18:46]

Hmm, now it occurs to me that this might cause the close button to show on any
Mac dialogs that don't use BubbleFrameView... I'm not sure if any Mac dialog
windows use other frames... you might want to try asking around/auditing, taking
a look at DialogDelegate::CreateNonClientFrameView/GetDialogWidgetInitParams and
maybe adding DCHECK[s] there to ensure Mac only ever makes dialog frames with
bubble frame views (or trying to hide other frames' close buttons...).

-#else
   return true;
-#endif
 }
 
 bool WidgetDelegate::ShouldHandleSystemCommands() const {
   const Widget* widget = GetWidget();
   if (!widget)
     return false;
 
   return widget->non_client_view() != NULL;
 }
 
@@ skipping 109 matching lines @@
 
 const Widget* WidgetDelegateView::GetWidget() const {
   return View::GetWidget();
 }
 
 const char* WidgetDelegateView::GetClassName() const {
   return kViewClassName;
 }
 
 }  // namespace views