Add iterator support to blink::EventPath.

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

 /*
  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2001 Tobias Anton (anton@stud.fbi.fh-darmstadt.de)
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 283 matching lines @@
     DCHECK(!m_eventPath->isEmpty());
     // After dispatching the event
     if (mode == EmptyAfterDispatch)
       return HeapVector<Member<EventTarget>>();
     return m_eventPath->last().treeScopeEventContext().ensureEventPath(
         *m_eventPath);
   }
 
   if (Node* node = m_currentTarget->toNode()) {
     DCHECK(m_eventPath);
-    size_t eventPathSize = m_eventPath->size();
-    for (size_t i = 0; i < eventPathSize; ++i) {
-      if (node == (*m_eventPath)[i].node()) {
-        return (*m_eventPath)[i].treeScopeEventContext().ensureEventPath(
-            *m_eventPath);
-      }
+    for (auto& context : m_eventPath->nodeEventContexts()) {
+      if (node == context.node())
+        return context.treeScopeEventContext().ensureEventPath(*m_eventPath);
     }
     NOTREACHED();
   }
 
   if (LocalDOMWindow* window = m_currentTarget->toLocalDOMWindow()) {
     if (m_eventPath && !m_eventPath->isEmpty()) {
       return m_eventPath->topNodeEventContext()
           .treeScopeEventContext()
           .ensureEventPath(*m_eventPath);
     }
@@ skipping 28 matching lines @@
 }
 
 DEFINE_TRACE(Event) {
   visitor->trace(m_currentTarget);
   visitor->trace(m_target);
   visitor->trace(m_underlyingEvent);
   visitor->trace(m_eventPath);
 }
 
 }  // namespace blink