Handle WebContentsViewMac being destroyed while a <select> menu is showing.

content/browser/frame_host/popup_menu_helper_mac.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 CONTENT_BROWSER_FRAME_HOST_POPUP_MENU_HELPER_MAC_H_
 #define CONTENT_BROWSER_FRAME_HOST_POPUP_MENU_HELPER_MAC_H_
 
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "ui/gfx/geometry/rect.h"
 
 #ifdef __OBJC__
 @class WebMenuRunner;
 #else
 class WebMenuRunner;
 #endif
 
 namespace content {
 
 class RenderFrameHost;
 class RenderFrameHostImpl;
 class RenderWidgetHostViewMac;
 struct MenuItem;
 
 class PopupMenuHelper : public NotificationObserver {
  public:
+  class Delegate {
+   public:
+    virtual void OnMenuClosed() = 0;
+  };
+
   // Creates a PopupMenuHelper that will notify |render_frame_host| when a user
-  // selects or cancels the popup.
-  explicit PopupMenuHelper(RenderFrameHost* render_frame_host);
+  // selects or cancels the popup. |delegate| is notified when the menu is
+  // closed.
+  PopupMenuHelper(Delegate* delegate, RenderFrameHost* render_frame_host);
+  ~PopupMenuHelper() override;
   void Hide();
 
   // Shows the popup menu and notifies the RenderFrameHost of the selection/
   // cancellation. This call is blocking.
   void ShowPopupMenu(const gfx::Rect& bounds,
                      int item_height,
                      double item_font_size,
                      int selected_item,
                      const std::vector<MenuItem>& items,
                      bool right_aligned,
                      bool allow_multiple_selection);
 
   // Immediately return from ShowPopupMenu.
   CONTENT_EXPORT static void DontShowPopupMenuForTesting();
 
  protected:
   virtual RenderWidgetHostViewMac* GetRenderWidgetHostView() const;
 
+ private:
   // NotificationObserver implementation:
   void Observe(int type,
                const NotificationSource& source,
                const NotificationDetails& details) override;
 
+  Delegate* delegate_;  // Weak. Owns |this|.
+
   NotificationRegistrar notification_registrar_;
   RenderFrameHostImpl* render_frame_host_;
   WebMenuRunner* menu_runner_;
   bool popup_was_hidden_;
 
+  base::WeakPtrFactory<PopupMenuHelper> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(PopupMenuHelper);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_POPUP_MENU_HELPER_MAC_H_