Move undo files into //components/undo

chrome/browser/undo/undo_manager_observer.h

Index: chrome/browser/undo/undo_manager_observer.h
diff --git a/chrome/browser/undo/undo_manager_observer.h b/chrome/browser/undo/undo_manager_observer.h
deleted file mode 100644
index c61aea25ba644dea4d00522e56d6cc97401641de..0000000000000000000000000000000000000000
--- a/chrome/browser/undo/undo_manager_observer.h
+++ /dev/null
@@ -1,18 +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 CHROME_BROWSER_UNDO_UNDO_MANAGER_OBSERVER_H_
-#define CHROME_BROWSER_UNDO_UNDO_MANAGER_OBSERVER_H_
-
-// Observer for the UndoManager.
-class UndoManagerObserver {
- public:
-  // Invoked when the internal state of the UndoManager has changed.
-  virtual void OnUndoManagerStateChange() = 0;
-
- protected:
-  virtual ~UndoManagerObserver() {}
-};
-
-#endif  // CHROME_BROWSER_UNDO_UNDO_MANAGER_OBSERVER_H_