It is time.

ui/views/mouse_watcher.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_VIEWS_MOUSE_WATCHER_H_
-#define UI_VIEWS_MOUSE_WATCHER_H_
-
-#include "base/basictypes.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/time/time.h"
-#include "ui/gfx/insets.h"
-#include "ui/views/views_export.h"
-
-namespace gfx {
-class Point;
-}
-
-namespace views {
-
-// MouseWatcherListener is notified when the mouse moves outside the host.
-class VIEWS_EXPORT MouseWatcherListener {
- public:
-  virtual void MouseMovedOutOfHost() = 0;
-
- protected:
-  virtual ~MouseWatcherListener();
-};
-
-// The MouseWatcherHost determines what region is to be monitored.
-class VIEWS_EXPORT MouseWatcherHost {
- public:
-  // The MouseEventType can be used as a hint.
-  enum MouseEventType {
-    // The mouse moved within the window which was current when the MouseWatcher
-    // was created.
-    MOUSE_MOVE,
-    // The mouse moved exited the window which was current when the MouseWatcher
-    // was created.
-    MOUSE_EXIT
-  };
-
-  virtual ~MouseWatcherHost();
-
-  // Return false when the mouse has moved outside the monitored region.
-  virtual bool Contains(const gfx::Point& screen_point,
-                        MouseEventType type) = 0;
-};
-
-// MouseWatcher is used to watch mouse movement and notify its listener when the
-// mouse moves outside the bounds of a MouseWatcherHost.
-class VIEWS_EXPORT MouseWatcher {
- public:
-  // Creates a new MouseWatcher. The |listener| will be notified when the |host|
-  // determines that the mouse has moved outside its monitored region.
-  // |host| will be owned by the watcher and deleted upon completion.
-  MouseWatcher(MouseWatcherHost* host, MouseWatcherListener* listener);
-  ~MouseWatcher();
-
-  // Sets the amount to delay before notifying the listener when the mouse exits
-  // the host by way of going to another window.
-  void set_notify_on_exit_time(base::TimeDelta time) {
-    notify_on_exit_time_ = time;
-  }
-
-  // Starts watching mouse movements. When the mouse moves outside the bounds of
-  // the host the listener is notified. |Start| may be invoked any number of
-  // times. If the mouse moves outside the bounds of the host the listener is
-  // notified and watcher stops watching events.
-  void Start();
-
-  // Stops watching mouse events.
-  void Stop();
-
- private:
-  class Observer;
-
-  // Are we currently observing events?
-  bool is_observing() const { return observer_.get() != NULL; }
-
-  // Notifies the listener and stops watching events.
-  void NotifyListener();
-
-  // Host we're listening for events over.
-  scoped_ptr<MouseWatcherHost> host_;
-
-  // Our listener.
-  MouseWatcherListener* listener_;
-
-  // Does the actual work of listening for mouse events.
-  scoped_ptr<Observer> observer_;
-
-  // See description above setter.
-  base::TimeDelta notify_on_exit_time_;
-
-  DISALLOW_COPY_AND_ASSIGN(MouseWatcher);
-};
-
-}  // namespace views
-
-#endif  // UI_VIEWS_MOUSE_WATCHER_H_