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

third_party/WebKit/Source/core/events/EventTarget.cpp

 /*
  * 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 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  *           (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ skipping 349 matching lines @@
   size_t indexOfRemovedListener;
   RegisteredEventListener registeredListener;
 
   if (!d->eventListenerMap.remove(eventType, listener, options,
                                   &indexOfRemovedListener, &registeredListener))
     return false;
 
   // Notify firing events planning to invoke the listener at 'index' that
   // they have one less listener to invoke.
   if (d->firingEventIterators) {
-    for (size_t i = 0; i < d->firingEventIterators->size(); ++i) {
-      FiringEventIterator& firingIterator = d->firingEventIterators->at(i);
+    for (const auto& firingIterator : *d->firingEventIterators) {
       if (eventType != firingIterator.eventType)
         continue;
 
       if (indexOfRemovedListener >= firingIterator.end)
         continue;
 
       --firingIterator.end;
       // Note that when firing an event listener,
       // firingIterator.iterator indicates the next event listener
       // that would fire, not the currently firing event
@@ skipping 361 matching lines @@
 
 void EventTarget::removeAllEventListeners() {
   EventTargetData* d = eventTargetData();
   if (!d)
     return;
   d->eventListenerMap.clear();
 
   // Notify firing events planning to invoke the listener at 'index' that
   // they have one less listener to invoke.
   if (d->firingEventIterators) {
-    for (size_t i = 0; i < d->firingEventIterators->size(); ++i) {
-      d->firingEventIterators->at(i).iterator = 0;
-      d->firingEventIterators->at(i).end = 0;
+    for (const auto& iterator : *d->firingEventIterators) {
+      iterator.iterator = 0;
+      iterator.end = 0;
     }
   }
 }
 
 }  // namespace blink