Demo patch that demonstrates simple block layout using Layout NG

third_party/WebKit/Source/core/layout/ng/ng_box_iterator.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/layout/ng/ng_box_iterator.h"
+#include "core/layout/ng/ng_box.h"
+
+namespace blink {
+
+NGBoxIterator::NGBoxIterator(LayoutObject* layoutObject)
+    : m_layoutObject(layoutObject) {}
+
+NGBoxIterator::iterator& NGBoxIterator::iterator::operator=(
+    const NGBoxIterator::iterator& otherValue) {
+  m_layoutObject = otherValue.m_layoutObject;
+  return (*this);
+}
+
+NGBoxIterator::iterator& NGBoxIterator::iterator::operator++() {
+  if (m_layoutObject)
+    m_layoutObject = m_layoutObject->nextSibling();
+  return (*this);
+}
+
+bool NGBoxIterator::iterator::operator!=(const iterator& other) {
+  return m_layoutObject != other.m_layoutObject;
+}
+
+NGBox NGBoxIterator::iterator::operator*() {
+  return NGBox(m_layoutObject);
+}
+
+NGBoxIterator::iterator NGBoxIterator::begin() const {
+  if (m_layoutObject)
+    return iterator(m_layoutObject->slowFirstChild());
+  return iterator(nullptr);
+}
+
+}  // namespace blink