ExternalPopupMenu should recreate its popup only if a SELECT subtree is updated

third_party/WebKit/Source/core/loader/EmptyClients.cpp

 /*
  * Copyright (C) 2006 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 45 matching lines @@
 
     DEFINE_STATIC_LOCAL(EmptySpellCheckerClient, dummySpellCheckerClient, ());
     pageClients.spellCheckerClient = &dummySpellCheckerClient;
 }
 
 class EmptyPopupMenu : public PopupMenu {
 public:
     void show() override { }
     void hide() override { }
     void updateFromElement() override { }
+    void updateFromElementWithMutation() override { }
     void disconnectClient() override { }
 };
 
 class EmptyFrameScheduler : public WebFrameScheduler {
 public:
     void setFrameVisible(bool) override { }
     WebTaskRunner* loadingTaskRunner() override;
     WebTaskRunner* timerTaskRunner() override;
 };
 
@@ skipping 95 matching lines @@
 {
     return nullptr;
 }
 
 PassOwnPtr<WebApplicationCacheHost> EmptyFrameLoaderClient::createApplicationCacheHost(WebApplicationCacheHostClient*)
 {
     return nullptr;
 }
 
 } // namespace blink