Use CustomFrameViewAsh in ash::Shell::CreateDefaultNonClientFrameView.

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index 09190d7794facbca441f8ad6ba5c8a9c03cac508..0f12d3f7cbcf39013129b5fa9eca1d536202ee3f 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -100,7 +100,6 @@
 #include "ui/views/focus/focus_manager_factory.h"
 #include "ui/views/widget/native_widget_aura.h"
 #include "ui/views/widget/widget.h"
-#include "ui/views/window/dialog_delegate.h"
 
 #if !defined(OS_MACOSX)
 #include "ash/accelerators/accelerator_controller.h"
@@ -688,8 +687,6 @@ bool Shell::IsSystemModalWindowOpen() const {
 
 views::NonClientFrameView* Shell::CreateDefaultNonClientFrameView(
     views::Widget* widget) {
-  if (views::DialogDelegate::UseNewStyle())
-    return views::DialogDelegate::CreateNewStyleFrameView(widget);
   // Use translucent-style window frames for dialogs.
   CustomFrameViewAsh* frame_view = new CustomFrameViewAsh;
   frame_view->Init(widget);