PopupMenuImpl should get menu items via PopupMenuClient.

Source/core/layout/LayoutMenuList.h

 /*
  * This file is part of the select element layoutObject in WebCore.
  *
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 63 matching lines @@
     bool hasControlClip() const override { return true; }
 
     void computeIntrinsicLogicalWidths(LayoutUnit& minLogicalWidth, LayoutUnit& maxLogicalWidth) const override;
 
     void styleDidChange(StyleDifference, const ComputedStyle* oldStyle) override;
 
     // PopupMenuClient methods
     void valueChanged(unsigned listIndex, bool fireOnChange = true) override;
     void selectionChanged(unsigned, bool) override { }
     void selectionCleared() override { }
+    Element& itemElement(unsigned listIndex) const override;
     String itemText(unsigned listIndex) const override;
     String itemToolTip(unsigned listIndex) const override;
     String itemAccessibilityText(unsigned listIndex) const override;
     bool itemIsEnabled(unsigned listIndex) const override;
     bool itemIsDisplayNone(unsigned listIndex) const override;
     LayoutUnit clientPaddingLeft() const override;
     LayoutUnit clientPaddingRight() const override;
     int listSize() const override;
     int selectedIndex() const override;
     void popupDidHide() override;
     void popupDidCancel() override;
     bool itemIsSeparator(unsigned listIndex) const override;
     bool itemIsLabel(unsigned listIndex) const override;
     bool itemIsSelected(unsigned listIndex) const override;
     void provisionalSelectionChanged(unsigned) override;
     void listBoxSelectItem(int listIndex, bool allowMultiplySelections, bool shift, bool fireOnChangeNow = true) override;
     bool multiple() const override;
     IntRect elementRectRelativeToViewport() const override;
     Element& ownerElement() const override;
-    const ComputedStyle* computedStyleForItem(Element&) const override;
 
     bool hasLineIfEmpty() const override { return true; }
 
     // Flexbox defines baselines differently than regular blocks.
     // For backwards compatibility, menulists need to do the regular block behavior.
     int baselinePosition(FontBaseline baseline, bool firstLine, LineDirectionMode direction, LinePositionMode position) const override
     {
         return LayoutBlock::baselinePosition(baseline, firstLine, direction, position);
     }
     int firstLineBoxBaseline() const override { return LayoutBlock::firstLineBoxBaseline(); }
@@ skipping 27 matching lines @@
 
     // TODO(tkent): Use FRIEND_TEST macro provided by gtest_prod.h
     friend class LayoutMenuListTest_ElementRectRelativeToViewport_Test;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutMenuList, isMenuList());
 
 }
 
 #endif