Add support for Element.getAttributeNames()

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc.
  * All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
@@ skipping 306 matching lines @@
 NamedNodeMap* Element::attributesForBindings() const {
   ElementRareData& rare_data =
       const_cast<Element*>(this)->EnsureElementRareData();
   if (NamedNodeMap* attribute_map = rare_data.AttributeMap())
     return attribute_map;
 
   rare_data.SetAttributeMap(NamedNodeMap::Create(const_cast<Element*>(this)));
   return rare_data.AttributeMap();
 }
 
+Vector<AtomicString> Element::getAttributeNames() const {
+  Vector<AtomicString> attributesVector;
+  if (!hasAttributes())
+    return attributesVector;
+
+  AttributeCollection attributes = element_data_->Attributes();
+  attributesVector.ReserveInitialCapacity(attributes.size());
+  for (const Attribute& attr : attributes)
+    attributesVector.UncheckedAppend(attr.GetName().ToString());
+  return attributesVector;
+}
+
 ElementAnimations* Element::GetElementAnimations() const {
   if (HasRareData())
     return GetElementRareData()->GetElementAnimations();
   return nullptr;
 }
 
 ElementAnimations& Element::EnsureElementAnimations() {
   ElementRareData& rare_data = EnsureElementRareData();
   if (!rare_data.GetElementAnimations())
     rare_data.SetElementAnimations(new ElementAnimations());
@@ skipping 4020 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(Element) {
   if (HasRareData()) {
     visitor->TraceWrappers(GetElementRareData());
   }
   ContainerNode::TraceWrappers(visitor);
 }
 
 }  // namespace blink