Revert "chromeos: Move files in //ash/common to //ash, part 2"

ash/wm/workspace/workspace_layout_manager_backdrop_delegate.h

Index: ash/wm/workspace/workspace_layout_manager_backdrop_delegate.h
diff --git a/ash/wm/workspace/workspace_layout_manager_backdrop_delegate.h b/ash/wm/workspace/workspace_layout_manager_backdrop_delegate.h
deleted file mode 100644
index ed20222ec26bf99e033414279e5ae2536001249f..0000000000000000000000000000000000000000
--- a/ash/wm/workspace/workspace_layout_manager_backdrop_delegate.h
+++ /dev/null
@@ -1,48 +0,0 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef ASH_WM_WORKSPACE_WORKSPACE_LAYOUT_MANAGER_BACKDROP_DELEGATE_H_
-#define ASH_WM_WORKSPACE_WORKSPACE_LAYOUT_MANAGER_BACKDROP_DELEGATE_H_
-
-#include "ash/ash_export.h"
-#include "ash/wm/wm_types.h"
-
-namespace ash {
-
-class WmWindow;
-
-namespace wm {
-class WindowState;
-}
-
-// A delegate which can be set to create and control a backdrop which gets
-// placed below the top level window.
-class ASH_EXPORT WorkspaceLayoutManagerBackdropDelegate {
- public:
-  virtual ~WorkspaceLayoutManagerBackdropDelegate() {}
-
-  // A window got added to the layout.
-  virtual void OnWindowAddedToLayout(WmWindow* child) = 0;
-
-  // A window got removed from the layout.
-  virtual void OnWindowRemovedFromLayout(WmWindow* child) = 0;
-
-  // The visibility of a window has changed.
-  virtual void OnChildWindowVisibilityChanged(WmWindow* child,
-                                              bool visible) = 0;
-
-  // The stacking order of a window has changed.
-  virtual void OnWindowStackingChanged(WmWindow* window) = 0;
-
-  // A window state type has changed.
-  virtual void OnPostWindowStateTypeChange(wm::WindowState* window_state,
-                                           wm::WindowStateType old_type) = 0;
-
-  // The work area insets have changed, altering the total available space.
-  virtual void OnDisplayWorkAreaInsetsChanged() = 0;
-};
-
-}  // namespace ash
-
-#endif  // ASH_WM_WORKSPACE_WORKSPACE_LAYOUT_MANAGER_BACKDROP_DELEGATE_H_