Improve performance of HTMLSelectElement::m_listItems update.

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 72 matching lines @@
     String value() const;
     void setValue(const String&, bool sendEvents = false);
     String suggestedValue() const;
     void setSuggestedValue(const String&);
 
     HTMLOptionsCollection* options();
     HTMLCollection* selectedOptions();
 
     void optionElementChildrenChanged(const HTMLOptionElement&);
 
-    void setRecalcListItems();
     void invalidateSelectedItems();
 
     using ListItems = HeapVector<Member<HTMLElement>>;
     const ListItems& listItems() const;
 
     void accessKeyAction(bool sendMouseEvents) override;
     void accessKeySetSelectedIndex(int);
 
     void setOption(unsigned index, HTMLOptionElement*, ExceptionState&);
 
@@ skipping 11 matching lines @@
     void listBoxOnChange();
     int optionToListIndex(int optionIndex) const;
     int activeSelectionEndListIndex() const;
     HTMLOptionElement* activeSelectionEnd() const;
     void setActiveSelectionAnchor(HTMLOptionElement*);
     void setActiveSelectionEnd(HTMLOptionElement*);
 
     // For use in the implementation of HTMLOptionElement.
     void optionSelectionStateChanged(HTMLOptionElement*, bool optionIsSelected);
     void optionInserted(HTMLOptionElement&, bool optionIsSelected);
-    void optionRemoved(const HTMLOptionElement&);
+    void optionRemoved(HTMLOptionElement&);
     bool anonymousIndexedSetter(unsigned, HTMLOptionElement*, ExceptionState&);
 
-    void optGroupInsertedOrRemoved(const HTMLOptGroupElement&);
-    void hrInsertedOrRemoved(const HTMLHRElement&);
+    void optGroupInsertedOrRemoved(HTMLOptGroupElement&);
+    void hrInsertedOrRemoved(HTMLHRElement&);
 
     void updateListOnLayoutObject();
 
     HTMLOptionElement* spatialNavigationFocusedOption();
     void handleMouseRelease();
 
     int listIndexForOption(const HTMLOptionElement&);
 
     // Helper functions for popup menu implementations.
     String itemText(const Element&) const;
@@ skipping 50 matching lines @@
     LayoutObject* createLayoutObject(const ComputedStyle&) override;
     void didRecalcStyle(StyleRecalcChange) override;
     void detach(const AttachContext& = AttachContext()) override;
     void appendToFormData(FormData&) override;
     void didAddUserAgentShadowRoot(ShadowRoot&) override;
 
     void defaultEventHandler(Event*) override;
 
     void dispatchInputAndChangeEventForMenuList();
 
+    // |subject| is an element which was inserted or removed.
+    void setRecalcListItems(HTMLElement& subject);
     void recalcListItems() const;
     enum ResetReason {
         ResetReasonSelectedOptionRemoved,
         ResetReasonOthers
     };
     void resetToDefaultSelection(ResetReason = ResetReasonOthers);
     void typeAheadFind(KeyboardEvent*);
     void saveLastSelection();
     void saveListboxActiveSelection();
     // Returns the first selected OPTION, or nullptr.
@@ skipping 77 matching lines @@
 
     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