chromeos: Rename ash::WmShelf to Shelf

ash/shelf/wm_shelf_observer.h

Index: ash/shelf/wm_shelf_observer.h
diff --git a/ash/shelf/wm_shelf_observer.h b/ash/shelf/wm_shelf_observer.h
deleted file mode 100644
index 55033bef25a21cdda96429ccebc8cf4f54fda5a5..0000000000000000000000000000000000000000
--- a/ash/shelf/wm_shelf_observer.h
+++ /dev/null
@@ -1,30 +0,0 @@
-// Copyright 2016 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_SHELF_WM_SHELF_OBSERVER_H_
-#define ASH_SHELF_WM_SHELF_OBSERVER_H_
-
-#include "ash/ash_export.h"
-#include "ash/public/cpp/shelf_types.h"
-
-namespace ash {
-
-enum class AnimationChangeType;
-
-// Used to observe changes to the shelf.
-class ASH_EXPORT WmShelfObserver {
- public:
-  virtual void OnBackgroundTypeChanged(ShelfBackgroundType background_type,
-                                       AnimationChangeType change_type) {}
-  virtual void WillChangeVisibilityState(ShelfVisibilityState new_state) {}
-  virtual void OnAutoHideStateChanged(ShelfAutoHideState new_state) {}
-  virtual void OnShelfIconPositionsChanged() {}
-
- protected:
-  virtual ~WmShelfObserver() {}
-};
-
-}  // namespace ash
-
-#endif  // ASH_SHELF_WM_SHELF_OBSERVER_H_