[LayoutNG] Initial version of NGBox wrapper object.

third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.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_block_layout_algorithm.h"
 
 #include "core/layout/LayoutBox.h"
 #include "core/layout/ng/ng_constraint_space.h"
 #include "core/layout/ng/ng_fragment.h"
 #include "core/style/ComputedStyle.h"
 #include "platform/LengthFunctions.h"
 
 namespace blink {
 
-NGBlockLayoutAlgorithm::NGBlockLayoutAlgorithm(const ComputedStyle* style)
-    : m_style(style) {}
+NGBlockLayoutAlgorithm::NGBlockLayoutAlgorithm(
+    PassRefPtr<const ComputedStyle> style,
+    NGBox firstChild)
+    : m_style(style), m_firstChild(firstChild) {}
 
 NGFragment* NGBlockLayoutAlgorithm::layout(
     const NGConstraintSpace& constraintSpace) {
   LayoutUnit inlineSize = valueForLength(m_style->logicalWidth(),
                                          constraintSpace.inlineContainerSize());
   LayoutUnit blockSize = valueForLength(m_style->logicalHeight(),
                                         constraintSpace.blockContainerSize());
+
+  for (NGBox curr = m_firstChild; curr; curr.nextSibling()) {
+    curr.layout(constraintSpace);
+  }
+
   return new NGFragment(inlineSize, blockSize, inlineSize, blockSize);
 }
 
 }  // namespace blink