ash/wm: Remove dead code.

ash/accelerators/nested_accelerator_delegate.h

-// 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_ACCELERATORS_NESTED_ACCELERATOR_DELEGATE_H_
-#define ASH_ACCELERATORS_NESTED_ACCELERATOR_DELEGATE_H_
-
-#include "base/macros.h"
-#include "ui/wm/core/nested_accelerator_delegate.h"
-
-namespace ash {
-
-class NestedAcceleratorDelegate : public wm::NestedAcceleratorDelegate {
- public:
-  NestedAcceleratorDelegate();
-  ~NestedAcceleratorDelegate() override;
-
-  // wm::AcceleratorDispatcher::Delegate
-  Result ProcessAccelerator(const ui::Accelerator& accelerator) override;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(NestedAcceleratorDelegate);
-};
-
-}  // namespace
-
-#endif  // ASH_ACCELERATORS_NESTED_ACCELERATOR_DELEGATE_H_