Don't updateRenderTree in the middle of a DOM insertion.

Source/core/html/HTMLSelectElement.cpp

 /*
  * 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) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
@@ skipping 66 matching lines @@
     , m_size(0)
     , m_lastOnChangeIndex(-1)
     , m_activeSelectionAnchorIndex(-1)
     , m_activeSelectionEndIndex(-1)
     , m_isProcessingUserDrivenChange(false)
     , m_multiple(false)
     , m_activeSelectionState(false)
     , m_shouldRecalcListItems(false)
     , m_suggestedIndex(-1)
     , m_isAutofilledByPreview(false)
-    , m_scrollToSelectionLater(false)
 {
 }
 
 PassRefPtrWillBeRawPtr<HTMLSelectElement> HTMLSelectElement::create(Document& document)
 {
     RefPtrWillBeRawPtr<HTMLSelectElement> select = adoptRefWillBeNoop(new HTMLSelectElement(document, 0));
     select->ensureUserAgentShadowRoot();
     return select.release();
 }
 
@@ skipping 314 matching lines @@
     setNeedsValidityCheck();
 }
 
 void HTMLSelectElement::childrenChanged(const ChildrenChange& change)
 {
     setRecalcListItems();
     setNeedsValidityCheck();
     m_lastOnChangeSelection.clear();
 
     HTMLFormControlElementWithState::childrenChanged(change);
-
-    if (m_scrollToSelectionLater) {
-        m_scrollToSelectionLater = false;
-        scrollToSelection();
-    }
 }
 
 void HTMLSelectElement::optionElementChildrenChanged()
 {
     setRecalcListItems();
     setNeedsValidityCheck();
 
     if (renderer()) {
         if (AXObjectCache* cache = renderer()->document().existingAXObjectCache())
             cache->childrenChanged(this);
@@ skipping 484 matching lines @@
     else if (!usesMenuList() || multiple())
         selectOption(-1);
     else
         selectOption(nextSelectableListIndex(-1));
 }
 
 void HTMLSelectElement::optionInserted(const HTMLOptionElement& option, bool optionIsSelected)
 {
     ASSERT(option.ownerSelectElement() == this);
     if (optionIsSelected)
-        selectOption(option.index(), DelayScrollToSelection);
+        selectOption(option.index());
 }
 
 void HTMLSelectElement::optionRemoved(const HTMLOptionElement& option)
 {
     if (m_activeSelectionAnchorIndex < 0 && m_activeSelectionEndIndex < 0)
         return;
     int listIndex = optionToListIndex(option.index());
     if (listIndex <= m_activeSelectionAnchorIndex)
         m_activeSelectionAnchorIndex--;
     if (listIndex <= m_activeSelectionEndIndex)
@@ skipping 24 matching lines @@
         }
     }
 
     if (shouldDeselect)
         deselectItemsWithoutValidation(element);
 
     // For the menu list case, this is what makes the selected element appear.
     if (RenderObject* renderer = this->renderer())
         renderer->updateFromElement();
 
-    if (flags & DelayScrollToSelection)
-        m_scrollToSelectionLater = true;
-    else
-        scrollToSelection();
-
+    scrollToSelection();
     setNeedsValidityCheck();
 
     if (usesMenuList()) {
         m_isProcessingUserDrivenChange = flags & UserDriven;
         if (flags & DispatchInputAndChangeEvent)
             dispatchInputAndChangeEventForMenuList();
         if (RenderObject* renderer = this->renderer()) {
             if (usesMenuList()) {
                 toRenderMenuList(renderer)->didSetSelectedIndex(listIndex);
             } else if (renderer->isListBox()) {
@@ skipping 794 matching lines @@
     int focusedIndex = activeSelectionEndListIndex();
     if (focusedIndex < 0)
         focusedIndex = firstSelectableListIndex();
     if (focusedIndex < 0)
         return nullptr;
     HTMLElement* focused = listItems()[focusedIndex];
     return isHTMLOptionElement(focused) ? toHTMLOptionElement(focused) : nullptr;
 }
 
 } // namespace