Add performance tests for adding options to a select element.

third_party/WebKit/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 48 matching lines @@
 #include "core/layout/LayoutMenuList.h"
 #include "core/layout/LayoutText.h"
 #include "core/layout/LayoutTheme.h"
 #include "core/layout/LayoutView.h"
 #include "core/page/AutoscrollController.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/Page.h"
 #include "core/page/SpatialNavigation.h"
 #include "platform/PlatformMouseEvent.h"
 #include "platform/PopupMenu.h"
+#include "platform/TraceEvent.h"
 #include "platform/text/PlatformLocale.h"
 
 using namespace WTF::Unicode;
 
 namespace blink {
 
 using namespace HTMLNames;
 
 // Upper limit of m_listItems. According to the HTML standard, options larger
 // than this limit doesn't work well because |selectedIndex| IDL attribute is
@@ skipping 711 matching lines @@
         invalidateSelectedItems();
 
     if (layoutObject()) {
         if (AXObjectCache* cache = layoutObject()->document().existingAXObjectCache())
             cache->childrenChanged(this);
     }
 }
 
 void HTMLSelectElement::recalcListItems(bool updateSelectedStates) const
 {
+    TRACE_EVENT0("blink", "HTMLSelectElement::recalcListItems");
     m_listItems.clear();
 
     m_shouldRecalcListItems = false;
 
     HTMLOptionElement* foundSelected = 0;
     HTMLOptionElement* firstOption = 0;
     for (Element* currentElement = ElementTraversal::firstWithin(*this); currentElement && m_listItems.size() < maxListItems; ) {
         if (!currentElement->isHTMLElement()) {
             currentElement = ElementTraversal::nextSkippingChildren(*currentElement, this);
             continue;
@@ skipping 145 matching lines @@
     if (listIndex <= m_activeSelectionEndIndex)
         m_activeSelectionEndIndex--;
     if (listIndex == selectedIndex())
         setAutofilled(false);
 }
 
 // TODO(tkent): This function is not efficient.  It contains multiple O(N)
 // operations.
 void HTMLSelectElement::selectOption(int optionIndex, SelectOptionFlags flags)
 {
+    TRACE_EVENT0("blink", "HTMLSelectElement::selectOption");
     bool shouldDeselect = !m_multiple || (flags & DeselectOtherOptions);
 
     const WillBeHeapVector<RawPtrWillBeMember<HTMLElement>>& items = listItems();
     // optionToListIndex is O(N).
     int listIndex = optionToListIndex(optionIndex);
 
     // selectedIndex() is O(N).
     if (selectedIndex() != optionIndex && isAutofilled())
         setAutofilled(false);
 
@@ skipping 981 matching lines @@
     m_popupIsVisible = false;
     m_popup = nullptr;
 }
 
 void HTMLSelectElement::resetTypeAheadSessionForTesting()
 {
     m_typeAhead.resetSession();
 }
 
 } // namespace blink