Widget::ShouldUseNativeFrame is now meaningful on Linux.

ui/views/widget/desktop_aura/desktop_native_widget_aura.cc

Index: ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
diff --git a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
index dd6a3cf0f80f40648098ab52b72c11c80d00796e..ece73faf75b93bae42691bdc848a76a7e09a0519 100644
--- a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
+++ b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
@@ -58,6 +58,7 @@
 #include "ui/views/widget/window_reorderer.h"
 
 #if defined(OS_WIN)
+#include "ui/base/win/shell.h"
 #include "ui/gfx/win/dpi.h"
 #endif
 
@@ -528,6 +529,10 @@ bool DesktopNativeWidgetAura::ShouldUseNativeFrame() const {
   return desktop_root_window_host_->ShouldUseNativeFrame();
 }
 
+bool DesktopNativeWidgetAura::ShouldWindowContentsBeTransparent() const {
+  return desktop_root_window_host_->ShouldWindowContentsBeTransparent();
+}
+
 void DesktopNativeWidgetAura::FrameTypeChanged() {
   desktop_root_window_host_->FrameTypeChanged();
   UpdateWindowTransparency();
@@ -1157,7 +1162,8 @@ void DesktopNativeWidgetAura::InstallInputMethodEventFilter() {
 }
 
 void DesktopNativeWidgetAura::UpdateWindowTransparency() {
-  content_window_->SetTransparent(ShouldUseNativeFrame());
+  content_window_->SetTransparent(
+      desktop_root_window_host_->ShouldWindowContentsBeTransparent());
 }
 
 }  // namespace views