mash: Migrate some system user files to common.

ash/root_window_controller.h

Index: ash/root_window_controller.h
diff --git a/ash/root_window_controller.h b/ash/root_window_controller.h
index 1b19fc6bd93d3a049c1545b00db93fc1966e0064..7d9b28b998547c9bb818ab6c728469f7ca61866f 100644
--- a/ash/root_window_controller.h
+++ b/ash/root_window_controller.h
@@ -11,7 +11,6 @@
 #include "ash/ash_export.h"
 #include "ash/common/shelf/shelf_types.h"
 #include "ash/common/shell_observer.h"
-#include "ash/system/user/login_status.h"
 #include "base/macros.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host.h"
@@ -55,6 +54,7 @@ class AlwaysOnTopController;
 class AnimatingDesktopController;
 class DesktopBackgroundWidgetController;
 class DockedWindowLayoutManager;
+enum class LoginStatus;

[msw, 2016/06/24 20:04:28]

WDYT about these forward decls? I'm on the fence...

[James Cook, 2016/06/24 20:18:53]

Either #include "ash/common/login_status.h" or forward declare, either way is
fine with me.

But let's not include "ash/system/user/login_status.h" just to get the enum.

[msw, 2016/06/24 20:26:46]

For sure, and I'd totally forward declare a class then include the header in the
cc file, but I'm just not used to doing the same with enums, and it feels a
little silly, but I'll leave the forward decls as they are in this patch set.

 class PanelLayoutManager;
 class RootWindowControllerCommon;
 class Shelf;