[LayoutNG] Move remaining ng_units structs to their own files

third_party/WebKit/Source/core/layout/ng/ng_min_max_content_size.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_min_max_content_size.h"
+
+namespace blink {
+
+LayoutUnit MinMaxContentSize::ShrinkToFit(LayoutUnit available_size) const {
+  DCHECK_GE(max_content, min_content);
+  return std::min(max_content, std::max(min_content, available_size));
+}
+
+bool MinMaxContentSize::operator==(const MinMaxContentSize& other) const {
+  return min_content == other.min_content && max_content == other.max_content;
+}
+
+std::ostream& operator<<(std::ostream& stream, const MinMaxContentSize& value) {
+  return stream << "(" << value.min_content << ", " << value.max_content << ")";
+}
+
+}  // namespace blink