MacViews: Don't draw custom frame on Mac

chrome/browser/ui/views/frame/browser_frame_ash.cc

 // Copyright 2013 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 "chrome/browser/ui/views/frame/browser_frame_ash.h"
 
 #include "ash/shell.h"
 #include "ash/wm/window_properties.h"
 #include "ash/wm/window_state.h"
 #include "ash/wm/window_state_delegate.h"
@@ skipping 121 matching lines @@
 
   params.context = ash::Shell::GetPrimaryRootWindow();
 #if defined(OS_WIN)
   // If this window is under ASH on Windows, we need it to be translucent.
   params.opacity = views::Widget::InitParams::TRANSLUCENT_WINDOW;
 #endif
 
   return params;
 }
 
+bool BrowserFrameAsh::UseCustomFrame() const {
+  return true;
+}
+
 bool BrowserFrameAsh::UsesNativeSystemMenu() const {
   return false;
 }
 
 int BrowserFrameAsh::GetMinimizeButtonOffset() const {
   return 0;
 }
 
 BrowserFrameAsh::~BrowserFrameAsh() {
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // BrowserFrameAsh, private:
 
 void BrowserFrameAsh::SetWindowAutoManaged() {
   if (!browser_view_->browser()->is_type_popup() ||
       browser_view_->browser()->is_app()) {
     ash::wm::GetWindowState(GetNativeWindow())->
         set_window_position_managed(true);
   }
 }