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

third_party/WebKit/Source/core/html/HTMLSelectElement.h

 /*
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 134 matching lines @@
     // A popup is canceled when the popup was hidden without selecting an item.
     void popupDidCancel();
     // Provisional selection is a selection made using arrow keys or type ahead.
     void provisionalSelectionChanged(unsigned);
     void popupDidHide();
     bool popupIsVisible() const { return m_popupIsVisible; }
     int optionIndexToBeShown() const;
     void showPopup();
     void hidePopup();
     PopupMenu* popup() const { return m_popup.get(); }
+    void didMutateSubtree();
 
     void resetTypeAheadSessionForTesting();
 
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     HTMLSelectElement(Document&, HTMLFormElement*);
 
 private:
     const AtomicString& formControlType() const override;
@@ skipping 77 matching lines @@
 
     void childrenChanged(const ChildrenChange&) override;
     bool areAuthorShadowsAllowed() const override { return false; }
     void finishParsingChildren() override;
 
     // TypeAheadDataSource functions.
     int indexOfSelectedOption() const override;
     int optionCount() const override;
     String optionAtIndex(int index) const override;
 
+    void observeTreeMutation();
+    void unobserveTreeMutation();
+
     // m_listItems contains HTMLOptionElement, HTMLOptGroupElement, and
     // HTMLHRElement objects.
     mutable ListItems m_listItems;
     Vector<bool> m_lastOnChangeSelection;
     Vector<bool> m_cachedStateForActiveSelection;
     TypeAhead m_typeAhead;
     unsigned m_size;
     Member<HTMLOptionElement> m_lastOnChangeOption;
     Member<HTMLOptionElement> m_activeSelectionAnchor;
     Member<HTMLOptionElement> m_activeSelectionEnd;
     Member<HTMLOptionElement> m_optionToScrollTo;
     bool m_multiple;
     bool m_activeSelectionState;
     mutable bool m_shouldRecalcListItems;
     int m_suggestedIndex;
     bool m_isAutofilledByPreview;
 
+    class PopupUpdater;
+    Member<PopupUpdater> m_popupUpdater;
     Member<PopupMenu> m_popup;
     int m_indexToSelectOnCancel;
     bool m_popupIsVisible;
 
     FRIEND_TEST_ALL_PREFIXES(HTMLSelectElementTest, FirstSelectableOption);
     FRIEND_TEST_ALL_PREFIXES(HTMLSelectElementTest, LastSelectableOption);
     FRIEND_TEST_ALL_PREFIXES(HTMLSelectElementTest, NextSelectableOption);
     FRIEND_TEST_ALL_PREFIXES(HTMLSelectElementTest, PreviousSelectableOption);
 };
 
 } // namespace blink
 
 #endif // HTMLSelectElement_h