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 2806 matching lines @@
       HasEventListeners(EventTypeNames::keyup))
     return true;
   if (!IsSVGElement())
     return false;
   return (HasEventListeners(EventTypeNames::focus) ||
           HasEventListeners(EventTypeNames::blur) ||
           HasEventListeners(EventTypeNames::focusin) ||
           HasEventListeners(EventTypeNames::focusout));
 }
 
+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;
+}
+
 bool Element::IsFocusable() const {
   // Style cannot be cleared out for non-active documents, so in that case the
   // needsLayoutTreeUpdateForNode check is invalid.
   DCHECK(!GetDocument().IsActive() ||
          !GetDocument().NeedsLayoutTreeUpdateForNode(*this));
   return isConnected() && SupportsFocus() && !IsInert() &&
          LayoutObjectIsFocusable();
 }
 
 bool Element::IsKeyboardFocusable() const {
@@ skipping 1515 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(Element) {
   if (HasRareData()) {
     visitor->TraceWrappers(GetElementRareData());
   }
   ContainerNode::TraceWrappers(visitor);
 }
 
 }  // namespace blink