Add tracing to custom elements operations

third_party/WebKit/Source/core/dom/custom/CustomElementReactionQueue.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/dom/custom/CustomElementReactionQueue.h"
 
+#include "core/dom/Element.h"
 #include "core/dom/custom/CustomElementReaction.h"
+#include "platform/tracing/TraceEvent.h"
 
 namespace blink {
 
 CustomElementReactionQueue::CustomElementReactionQueue() : m_index(0u) {}
 
 CustomElementReactionQueue::~CustomElementReactionQueue() {}
 
 DEFINE_TRACE(CustomElementReactionQueue) {
   visitor->trace(m_reactions);
 }
 
 void CustomElementReactionQueue::add(CustomElementReaction* reaction) {
   m_reactions.append(reaction);
 }
 
 // There is one queue per element, so this could be invoked
 // recursively.
 void CustomElementReactionQueue::invokeReactions(Element* element) {
+  TRACE_EVENT1("blink", "CustomElementReactionQueue::invokeReactions", "name",
+               element->localName().utf8());
   while (m_index < m_reactions.size()) {
     CustomElementReaction* reaction = m_reactions[m_index];
     m_reactions[m_index++] = nullptr;
     reaction->invoke(element);
   }
   // Unlike V0CustomElementsCallbackQueue, reactions are always
   // inserted by steps which bump the global element queue. This
   // means we do not need queue "owner" guards.
   // https://html.spec.whatwg.org/multipage/scripting.html#custom-element-reactions
   clear();
 }
 
 void CustomElementReactionQueue::clear() {
   m_index = 0;
   m_reactions.resize(0);
 }
 
 }  // namespace blink