event-rewrite: Clean up how events are rewritten.

ash/event_rewriter_delegate.h

-// Copyright (c) 2012 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_EVENT_REWRITER_DELEGATE_H_
-#define ASH_EVENT_REWRITER_DELEGATE_H_
-
-namespace ui {
-class KeyEvent;
-class LocatedEvent;
-}  // namespace aura
-
-namespace ash {
-
-// Delegate for rewriting or filtering an event.
-class EventRewriterDelegate {
- public:
-  enum Action {
-    ACTION_REWRITE_EVENT,
-    ACTION_DROP_EVENT,
-  };
-
-  virtual ~EventRewriterDelegate() {}
-
-  // A derived class can do either of the following:
-  // 1) Just return ACTION_DROP_EVENT to drop the |event|.
-  // 2) Rewrite the |event| and return ACTION_REWRITE_EVENT.
-  virtual Action RewriteOrFilterKeyEvent(ui::KeyEvent* event) = 0;
-  virtual Action RewriteOrFilterLocatedEvent(ui::LocatedEvent* event) = 0;
-};
-
-}  // namespace ash
-
-#endif  // ASH_EVENT_REWRITER_DELEGATE_H_