It is time.

ui/wm/core/focus_rules.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 UI_WM_CORE_FOCUS_RULES_H_
-#define UI_WM_CORE_FOCUS_RULES_H_
-
-#include "ui/wm/wm_export.h"
-
-namespace aura {
-class Window;
-}
-
-namespace wm {
-
-// Implemented by an object that establishes the rules about what can be
-// focused or activated.
-class WM_EXPORT FocusRules {
- public:
-  virtual ~FocusRules() {}
-
-  // Returns true if |window| is a toplevel window. Whether or not a window
-  // is considered toplevel is determined by a similar set of rules that
-  // govern activation and focus. Not all toplevel windows are activatable,
-  // call CanActivateWindow() to determine if a window can be activated.
-  virtual bool IsToplevelWindow(aura::Window* window) const = 0;
-  // Returns true if |window| can be activated or focused.
-  virtual bool CanActivateWindow(aura::Window* window) const = 0;
-  // For CanFocusWindow(), NULL is supported, because NULL is a valid focusable
-  // window (in the case of clearing focus).
-  virtual bool CanFocusWindow(aura::Window* window) const = 0;
-
-  // Returns the toplevel window containing |window|. Not all toplevel windows
-  // are activatable, call GetActivatableWindow() instead to return the
-  // activatable window, which might be in a different hierarchy.
-  // Will return NULL if |window| is not contained by a window considered to be
-  // a toplevel window.
-  virtual aura::Window* GetToplevelWindow(aura::Window* window) const = 0;
-  // Returns the activatable or focusable window given an attempt to activate or
-  // focus |window|. Some possible scenarios (not intended to be exhaustive):
-  // - |window| is a child of a non-focusable window and so focus must be set
-  //   according to rules defined by the delegate, e.g. to a parent.
-  // - |window| is an activatable window that is the transient parent of a modal
-  //   window, so attempts to activate |window| should result in the modal
-  //   transient being activated instead.
-  // These methods may return NULL if they are unable to find an activatable
-  // or focusable window given |window|.
-  virtual aura::Window* GetActivatableWindow(aura::Window* window) const = 0;
-  virtual aura::Window* GetFocusableWindow(aura::Window* window) const = 0;
-
-  // Returns the next window to activate in the event that |ignore| is no longer
-  // activatable. This function is called when something is happening to
-  // |ignore| that means it can no longer have focus or activation, including
-  // but not limited to:
-  // - it or its parent hierarchy is being hidden, or removed from the
-  //   RootWindow.
-  // - it is being destroyed.
-  // - it is being explicitly deactivated.
-  // |ignore| cannot be NULL.
-  virtual aura::Window* GetNextActivatableWindow(
-      aura::Window* ignore) const = 0;
-};
-
-}  // namespace wm
-
-#endif  // UI_WM_CORE_FOCUS_RULES_H_