mash: Convert FocusCycler to wm common types and move to //ash/common

ash/focus_cycler.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 FOCUS_CYCLER_H_
-#define FOCUS_CYCLER_H_
-
-#include <vector>
-
-#include "ash/ash_export.h"
-#include "base/compiler_specific.h"
-#include "base/macros.h"
-
-namespace views {
-class Widget;
-}  // namespace views
-
-namespace ash {
-
-// This class handles moving focus between a set of widgets and the main browser
-// window.
-class ASH_EXPORT FocusCycler {
- public:
-  enum Direction {
-    FORWARD,
-    BACKWARD
-  };
-
-  FocusCycler();
-  ~FocusCycler();
-
-  // Returns the widget the FocusCycler is attempting to activate or NULL if
-  // FocusCycler is not activating any widgets.
-  const views::Widget* widget_activating() const { return widget_activating_; }
-
-  // Add a widget to the focus cycle. The widget needs to have an
-  // AccessiblePaneView as the content view.
-  void AddWidget(views::Widget* widget);
-
-  // Remove a widget from the focus cycle.
-  void RemoveWidget(views::Widget* widget);
-
-  // Move focus to the next widget.
-  void RotateFocus(Direction direction);
-
-  // Moves focus the specified widget. Returns true if the widget was activated.
-  bool FocusWidget(views::Widget* widget);
-
- private:
-  std::vector<views::Widget*> widgets_;
-
-  // See description above getter.
-  views::Widget* widget_activating_;
-
-  DISALLOW_COPY_AND_ASSIGN(FocusCycler);
-};
-
-}  // namespace ash
-
-#endif  // FOCUS_CYCLER_H_