mash: wires up shadows for mash

ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc b/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
index c6a331c453d9fc59754ed3c495eefb863f772627..a6782f6906049086140a4ea9ca161c6136f74045 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc
@@ -482,6 +482,10 @@ bool DesktopWindowTreeHostWin::ShouldUseDesktopNativeCursorManager() const {
   return true;
 }
 
+bool DesktopWindowTreeHostWin::ShouldCreateVisibiltyController() const {
+  return false;

[msw, 2017/02/15 01:37:29]

I guess the wm shadow (and other VisibilityController functionality) is
cros-specific and so this is okay? Were we previously creating visibility
controllers for DesktopNativeWidgetAura on Windows? (perhaps they don't use
TRANSLUCENT_WINDOW?) It'd be nice if VisibilityController had a class comment

[sky, 2017/02/15 03:58:25]

This is wrong, it should be true.

+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // DesktopWindowTreeHostWin, WindowTreeHost implementation: