Widget::ShouldUseNativeFrame is now meaningful on Linux.

ui/views/widget/desktop_aura/desktop_native_widget_aura.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/desktop_aura/desktop_native_widget_aura.h"
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "ui/aura/client/activation_client.h"
 #include "ui/aura/client/aura_constants.h"
@@ skipping 1139 matching lines @@
   DCHECK(!input_method_event_filter_.get());
 
   input_method_event_filter_.reset(new corewm::InputMethodEventFilter(
       root_window_->host()->GetAcceleratedWidget()));
   input_method_event_filter_->SetInputMethodPropertyInRootWindow(
       root_window_->window());
   root_window_event_filter_->AddHandler(input_method_event_filter_.get());
 }
 
 void DesktopNativeWidgetAura::UpdateWindowTransparency() {
-  content_window_->SetTransparent(ShouldUseNativeFrame());
+  bool transparent = false;
+#if defined(OS_WIN)
+  // On Windows, a native frame implies Glass, so the window should be
+  // transparent.
+  transparent = ShouldUseNativeFrame();

[sky, 2014/02/03 21:53:03]

Add a method to DesktopRootWindow that determines this rather than ifdefs.

[Matt Giuca, 2014/02/05 23:25:31]

Done.

[sky, 2014/02/06 00:36:14]

This isn't quite what I was asking for. I'm saying add another method to
DesktopRootWindowHost named ShouldContentWindowBeTransparent. This way the
decision is left to the DesktopRootWindowHost and there are no ifdefs in DNWA.
Alternatively move UpdateWindowTransparency to DesktopRootWindowHost.

[Matt Giuca, 2014/02/07 09:13:11]

Done.

+#endif
+  content_window_->SetTransparent(transparent);
 }
 
 }  // namespace views