Add window overview mode behind --ash-enable-overview-mode flag to F5 key.

ash/wm/window_selector_controller.h

Index: ash/wm/window_selector_controller.h
diff --git a/ash/wm/window_selector_controller.h b/ash/wm/window_selector_controller.h
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index 0000000000000000000000000000000000000000..244ee2891c812c992a4e9c0dc41b77f9fb31817b
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+++ b/ash/wm/window_selector_controller.h
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+// Copyright (c) 2013 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_WM_WINDOW_SELECTOR_CONTROLLER_H_
+#define ASH_WM_WINDOW_SELECTOR_CONTROLLER_H_
+
+#include <list>
+#include <vector>
+
+#include "ash/ash_export.h"
+#include "ash/wm/window_selector_delegate.h"
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "ui/aura/window_observer.h"
+
+namespace aura {
+class Window;
+}
+
+namespace ash {
+
+class WindowSelector;
+
+// Manages a window selector which displays an overview of all windows and
+// allows selecting a window to activate it.
+class ASH_EXPORT WindowSelectorController
+    : public WindowSelectorDelegate {
+ public:
+  WindowSelectorController();
+  virtual ~WindowSelectorController();
+
+  // Returns true if selecting windows in an overview is enabled. This is false
+  // at certain times, such as when the lock screen is visible.
+  static bool CanSelect();
+
+  // Enters overview mode. This is essentially the window cycling mode however
+  // not released on releasing the alt key and allows selecting with the mouse
+  // or touch rather than keypresses.
+  void ToggleOverview();
+
+  // Returns true if window selection mode is active.
+  bool IsSelecting();
+
+  // WindowSelectorDelegate:
+  virtual void OnWindowSelected(aura::Window* window) OVERRIDE;
+  virtual void OnSelectionCanceled() OVERRIDE;
+
+ private:
+  scoped_ptr<WindowSelector> window_selector_;
+
+  DISALLOW_COPY_AND_ASSIGN(WindowSelectorController);
+};
+
+}  // namespace ash
+
+#endif  // ASH_WM_WINDOW_SELECTOR_CONTROLLER_H_