Refactors DockedWindowLayoutManager in terms of ash/wm/common

ash/system/chromeos/screen_security/screen_tray_item.h

Index: ash/system/chromeos/screen_security/screen_tray_item.h
diff --git a/ash/system/chromeos/screen_security/screen_tray_item.h b/ash/system/chromeos/screen_security/screen_tray_item.h
index 6e48357a55dd7525a7e6cd2c2e6ac201a635b0b0..83d808010863ecd8d5a33234f7c77e86e8d47080 100644
--- a/ash/system/chromeos/screen_security/screen_tray_item.h
+++ b/ash/system/chromeos/screen_security/screen_tray_item.h
@@ -123,7 +123,7 @@ class ASH_EXPORT ScreenTrayItem : public SystemTrayItem {
   views::View* CreateDefaultView(user::LoginStatus status) override = 0;
   void DestroyTrayView() override;
   void DestroyDefaultView() override;
-  void UpdateAfterShelfAlignmentChange(ShelfAlignment alignment) override;
+  void UpdateAfterShelfAlignmentChange(wm::ShelfAlignment alignment) override;
 
  private:
   tray::ScreenTrayView* tray_view_;