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

views/controls/menu/menu_host_gtk.h

-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// 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_GTK_H_
 #define VIEWS_CONTROLS_MENU_MENU_HOST_GTK_H_
 
+#include "views/controls/menu/menu_host.h"
 #include "views/widget/widget_gtk.h"
 
 namespace views {
 
 class SubmenuView;
 
 // MenuHost implementation for Gtk.
-class MenuHost : public WidgetGtk {
+class MenuHostGtk : public WidgetGtk, public MenuHost {
  public:
-  explicit MenuHost(SubmenuView* submenu);
+  explicit MenuHostGtk(SubmenuView* submenu);
+  virtual ~MenuHostGtk();
 
+  // MenuHost overrides.
   void Init(gfx::NativeWindow parent,
             const gfx::Rect& bounds,
             View* contents_view,
             bool do_capture);
-
-  gfx::NativeWindow GetNativeWindow();
-
-  void Show();
-  virtual void Hide();
-  virtual void HideWindow();
-  void DoCapture();
-  void ReleaseCapture();
+  virtual bool IsMenuHostVisible();
+  virtual void ShowMenuHost(bool do_capture);
+  virtual void HideMenuHost();
+  virtual void DestroyMenuHost();
+  virtual void SetMenuHostBounds(const gfx::Rect& bounds);
+  virtual void ReleaseMenuHostCapture();
+  virtual gfx::NativeWindow GetMenuHostWindow();
 
  protected:
   virtual RootView* CreateRootView();
 
-  virtual gboolean OnGrabBrokeEvent(GtkWidget* widget, GdkEvent* event);
-
   // Overriden to return false, we do NOT want to release capture on mouse
   // release.
   virtual bool ReleaseCaptureOnMouseReleased();
 
   // Overriden to also release pointer grab.
   virtual void ReleaseGrab();
 
+  virtual void OnDestroy(GtkWidget* object);
+  virtual gboolean OnGrabBrokeEvent(GtkWidget* widget, GdkEvent* event);
+
  private:
-  // If true, we've been closed.
-  bool closed_;
+  void DoCapture();
+
+  // If true, DestroyMenuHost has been invoked.
+  bool destroying_;
 
   // The view we contain.
   SubmenuView* submenu_;
 
   // Have we done a pointer grab?
   bool did_pointer_grab_;
 
-  DISALLOW_COPY_AND_ASSIGN(MenuHost);
+  DISALLOW_COPY_AND_ASSIGN(MenuHostGtk);
 };
 
 }  // namespace views
 
 #endif  // VIEWS_CONTROLS_MENU_MENU_HOST_GTK_H_