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

views/controls/menu/menu_controller.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_CONTROLLER_H_
 #define VIEWS_CONTROLS_MENU_MENU_CONTROLLER_H_
 
 #include "build/build_config.h"
 
 #include <list>
@@ skipping 20 matching lines @@
 // MenuController -------------------------------------------------------------
 
 // MenuController is used internally by the various menu classes to manage
 // showing, selecting and drag/drop for menus. All relevant events are
 // forwarded to the MenuController from SubmenuView and MenuHost.
 class MenuController : public MessageLoopForUI::Dispatcher {
  public:
   friend class MenuHostRootView;
   friend class MenuItemView;
 
+  // Enumeration of how the menu should exit.
+  enum ExitType {
+    // Don't exit.
+    EXIT_NONE,
+
+    // All menus, including nested, should be exited.
+    EXIT_ALL,
+
+    // Only the outermost menu should be exited.
+    EXIT_OUTERMOST,
+
+    // This is set if the menu is being closed as the result of one of the menus
+    // being destroyed.
+    EXIT_DESTROYED
+  };
+
   // If a menu is currently active, this returns the controller for it.
   static MenuController* GetActiveInstance();
 
   // Runs the menu at the specified location. If the menu was configured to
   // block, the selected item is returned. If the menu does not block this
   // returns NULL immediately.
   MenuItemView* Run(gfx::NativeWindow parent,
                     MenuButton* button,
                     MenuItemView* root,
                     const gfx::Rect& bounds,
                     MenuItemView::AnchorPosition position,
                     int* mouse_event_flags);
 
   // Whether or not Run blocks.
   bool IsBlockingRun() const { return blocking_run_; }
 
   // Sets the selection to menu_item, a value of NULL unselects everything.
   // If open_submenu is true and menu_item has a submenu, the submenu is shown.
   // If update_immediately is true, submenus are opened immediately, otherwise
   // submenus are only opened after a timer fires.
   //
   // Internally this updates pending_state_ immediatley, and if
   // update_immediately is true, CommitPendingSelection is invoked to
   // show/hide submenus and update state_.
   void SetSelection(MenuItemView* menu_item,
                     bool open_submenu,
                     bool update_immediately);
 
-  // Cancels the current Run. If all is true, any nested loops are canceled
-  // as well. This immediately hides all menus.
-  void Cancel(bool all);
+  // Cancels the current Run. See ExitType for a description of what happens
+  // with the various parameters.
+  void Cancel(ExitType type);
 
-  // An alternative to Cancel(true) that can be used with a OneShotTimer.
-  void CancelAll() { return Cancel(true); }
+  // An alternative to Cancel(EXIT_ALL) that can be used with a OneShotTimer.
+  void CancelAll() { Cancel(EXIT_ALL); }
 
   // Various events, forwarded from the submenu.
   //
   // NOTE: the coordinates of the events are in that of the
   // MenuScrollViewContainer.
   void OnMousePressed(SubmenuView* source, const MouseEvent& event);
   void OnMouseDragged(SubmenuView* source, const MouseEvent& event);
   void OnMouseReleased(SubmenuView* source, const MouseEvent& event);
   void OnMouseMoved(SubmenuView* source, const MouseEvent& event);
   void OnMouseEntered(SubmenuView* source, const MouseEvent& event);
   bool GetDropFormats(
       SubmenuView* source,
       int* formats,
       std::set<OSExchangeData::CustomFormat>* custom_formats);
   bool AreDropTypesRequired(SubmenuView* source);
   bool CanDrop(SubmenuView* source, const OSExchangeData& data);
   void OnDragEntered(SubmenuView* source, const DropTargetEvent& event);
   int OnDragUpdated(SubmenuView* source, const DropTargetEvent& event);
   void OnDragExited(SubmenuView* source);
   int OnPerformDrop(SubmenuView* source, const DropTargetEvent& event);
 
   // Invoked from the scroll buttons of the MenuScrollViewContainer.
   void OnDragEnteredScrollButton(SubmenuView* source, bool is_up);
   void OnDragExitedScrollButton(SubmenuView* source);
 
  private:
-  // Enumeration of how the menu should exit.
-  enum ExitType {
-    // Don't exit.
-    EXIT_NONE,
-
-    // All menus, including nested, should be exited.
-    EXIT_ALL,
-
-    // Only the outermost menu should be exited.
-    EXIT_OUTERMOST
-  };
-
   class MenuScrollTask;
 
   // Tracks selection information.
   struct State {
     State() : item(NULL), submenu_open(false) {}
 
     // The selected menu item.
     MenuItemView* item;
 
     // If item has a submenu this indicates if the submenu is showing.
@@ skipping 279 matching lines @@
   scoped_ptr<MenuScrollTask> scroll_task_;
 
   MenuButton* menu_button_;
 
   DISALLOW_COPY_AND_ASSIGN(MenuController);
 };
 
 }  // namespace views
 
 #endif  // VIEWS_CONTROLS_MENU_MENU_CONTROLLER_H_