Fixes possible crash if the window hosting a menu was closed while the

views/controls/menu/menu_host.h

+// Copyright (c) 2010 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 VIEWS_CONTROLS_MENU_MENU_HOST_H_
+#define VIEWS_CONTROLS_MENU_MENU_HOST_H_
+
+#include "gfx/native_widget_types.h"
+#include "gfx/rect.h"
+
+namespace views {
+
+class SubmenuView;
+class View;
+
+// SubmenuView uses a MenuHost to house the SubmenuView. MenuHost typically
+// extends the native Widget type, but is defined here for clarity of what
+// methods SubmenuView uses.
+//
+// SubmenuView owns the MenuHost. When SubmenuView is done with the MenuHost
+// |DestroyMenuHost| is invoked. The one exception to this is if the native
+// OS destroys the widget out from under us, in which case |MenuHostDestroyed|
+// is invoked back on the SubmenuView and the SubmenuView then drops references
+// to the MenuHost.
+class MenuHost {
+ public:
+  // Creates the platform specific MenuHost. Ownership passes to the caller.
+  static MenuHost* Create(SubmenuView* submenu_view);
+
+  // Initializes and shows the MenuHost.
+  virtual void Init(gfx::NativeWindow parent,
+                    const gfx::Rect& bounds,
+                    View* contents_view,
+                    bool do_capture) = 0;
+
+  // Returns true if the menu host is visible.
+  virtual bool IsMenuHostVisible() = 0;
+
+  // Shows the menu host. If |do_capture| is true the menu host should do a
+  // mouse grab.
+  virtual void ShowMenuHost(bool do_capture) = 0;
+
+  // Hides the menu host.
+  virtual void HideMenuHost() = 0;
+
+  // Destroys and deletes the menu host.
+  virtual void DestroyMenuHost() = 0;
+
+  // Sets the bounds of the menu host.
+  virtual void SetMenuHostBounds(const gfx::Rect& bounds) = 0;
+
+  // Releases a mouse grab installed by |ShowMenuHost|.
+  virtual void ReleaseMenuHostCapture() = 0;
+
+  // Returns the native window of the MenuHost.
+  virtual gfx::NativeWindow GetMenuHostWindow() = 0;
+
+ protected:
+  virtual ~MenuHost() {}
+};
+
+}  // namespace views
+
+#endif  // VIEWS_CONTROLS_MENU_MENU_HOST_H_