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

content/browser/browser_plugin/browser_plugin_popup_menu_helper_mac.mm

 // 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.
 
 #include "content/browser/browser_plugin/browser_plugin_popup_menu_helper_mac.h"
 
 #include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_view_mac.h"
 #include "content/public/browser/render_widget_host.h"
 
 namespace content {
 
 BrowserPluginPopupMenuHelper::BrowserPluginPopupMenuHelper(
     RenderFrameHostImpl* embedder_rfh,
     RenderFrameHost* guest_rfh)
-    : PopupMenuHelper(guest_rfh), embedder_rfh_(embedder_rfh) {}
+    : PopupMenuHelper(this, guest_rfh), embedder_rfh_(embedder_rfh) {}
 
 RenderWidgetHostViewMac*
     BrowserPluginPopupMenuHelper::GetRenderWidgetHostView() const {
   return static_cast<RenderWidgetHostViewMac*>(embedder_rfh_->GetView());
 }
 
+void BrowserPluginPopupMenuHelper::OnMenuClosed() {
+  // BrowserPluginGuest doesn't support cancellation of popup menus, so the
+  // MenuHelper is its own delegate and OnMenuClosed() is ignored.
+}
+
 }  // namespace content