Moves creation of LockLayoutManager to common code

ash/common/wm_root_window_controller.cc

Index: ash/common/wm_root_window_controller.cc
diff --git a/ash/common/wm_root_window_controller.cc b/ash/common/wm_root_window_controller.cc
index 30ec6c1544cb3f0b796a5534f66a3d1f299c0c3a..025958149de0511d632bb6b4c2e4f8c77bd11de5 100644
--- a/ash/common/wm_root_window_controller.cc
+++ b/ash/common/wm_root_window_controller.cc
@@ -11,6 +11,7 @@
 #include "ash/common/wallpaper/wallpaper_delegate.h"
 #include "ash/common/wallpaper/wallpaper_widget_controller.h"
 #include "ash/common/wm/container_finder.h"
+#include "ash/common/wm/lock_layout_manager.h"
 #include "ash/common/wm/root_window_layout_manager.h"
 #include "ash/common/wm/system_modal_container_layout_manager.h"
 #include "ash/common/wm/window_state.h"
@@ -440,6 +441,11 @@ void WmRootWindowController::CreateLayoutManagers() {
   lock_modal_container->SetLayoutManager(
       base::MakeUnique<SystemModalContainerLayoutManager>(
           lock_modal_container));
+
+  WmWindow* lock_container = GetContainer(kShellWindowId_LockScreenContainer);
+  DCHECK(lock_container);
+  lock_container->SetLayoutManager(
+      base::MakeUnique<LockLayoutManager>(lock_container));
 }
 
 void WmRootWindowController::DeleteWorkspaceController() {