Avoid WTF::Vector::at() and operator[] in core/dom.

third_party/WebKit/Source/core/dom/shadow/ElementShadowV0.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 146 matching lines @@
   return it == m_nodeToInsertionPoints.end() ? nullptr : it->value;
 }
 
 void ElementShadowV0::distribute() {
   HeapVector<Member<HTMLShadowElement>, 32> shadowInsertionPoints;
   DistributionPool pool(m_elementShadow->host());
 
   for (ShadowRoot* root = &youngestShadowRoot(); root;
        root = root->olderShadowRoot()) {
     HTMLShadowElement* shadowInsertionPoint = 0;
-    const HeapVector<Member<InsertionPoint>>& insertionPoints =
-        root->descendantInsertionPoints();
-    for (size_t i = 0; i < insertionPoints.size(); ++i) {
-      InsertionPoint* point = insertionPoints[i];
+    for (const auto& point : root->descendantInsertionPoints()) {
       if (!point->isActive())
         continue;
       if (isHTMLShadowElement(*point)) {
         DCHECK(!shadowInsertionPoint);
         shadowInsertionPoint = toHTMLShadowElement(point);
         shadowInsertionPoints.append(shadowInsertionPoint);
       } else {
         pool.distributeTo(point, this);
         if (ElementShadow* shadow =
                 shadowWhereNodeCanBeDistributedForV0(*point))
@@ skipping 81 matching lines @@
 
 DEFINE_TRACE(ElementShadowV0) {
   visitor->trace(m_elementShadow);
   visitor->trace(m_nodeToInsertionPoints);
   visitor->trace(m_selectFeatures);
 }
 
 DEFINE_TRACE_WRAPPERS(ElementShadowV0) {}
 
 }  // namespace blink