Add iterator support to blink::EventPath.

third_party/WebKit/Source/core/dom/TreeScope.cpp

 /*
  * Copyright (C) 2011 Google Inc. All Rights Reserved.
  * Copyright (C) 2012 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 392 matching lines @@
     return nullptr;
 
   if (rootNode().isInV1ShadowTree()) {
     if (Element* retargeted = retarget(*element)) {
       return (this == &retargeted->treeScope()) ? retargeted : nullptr;
     }
     return nullptr;
   }
 
   EventPath* eventPath = new EventPath(*element);
-  for (size_t i = 0; i < eventPath->size(); ++i) {
-    if (eventPath->at(i).node() == rootNode()) {
-      // eventPath->at(i).target() is one of the followings:
+  for (const auto& context : eventPath->nodeEventContexts()) {
+    if (context.node() == rootNode()) {
+      // context.target() is one of the followings:
       // - InsertionPoint
       // - shadow host
       // - Document::focusedElement()
       // So, it's safe to do toElement().
-      return toElement(eventPath->at(i).target()->toNode());
+      return toElement(context.target()->toNode());
     }
   }
   return nullptr;
 }
 
 Element* TreeScope::adjustedElement(const Element& target) const {
   const Element* adjustedTarget = &target;
   for (const Element* ancestor = &target; ancestor;
        ancestor = ancestor->ownerShadowHost()) {
     // This adjustment is done only for V1 shadows, and is skipped for V0 or UA
@@ skipping 131 matching lines @@
   visitor->trace(m_parentTreeScope);
   visitor->trace(m_idTargetObserverRegistry);
   visitor->trace(m_selection);
   visitor->trace(m_elementsById);
   visitor->trace(m_imageMapsByName);
   visitor->trace(m_scopedStyleResolver);
   visitor->trace(m_radioButtonGroupScope);
 }
 
 }  // namespace blink