[LayoutNG] Move remaining ng_units structs to their own files

third_party/WebKit/Source/core/layout/ng/geometry/ng_logical_size.h

 // 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.
 
 #ifndef NGLogicalSize_h
 #define NGLogicalSize_h
 
 #include "core/CoreExport.h"
 #include "core/layout/ng/ng_writing_mode.h"
 #include "platform/LayoutUnit.h"
 
 namespace blink {
 
 struct NGPhysicalSize;
+#define NGSizeIndefinite LayoutUnit(-1)
 
 // NGLogicalSize is the size of rect (typically a fragment) in the logical
 // coordinate system.
 struct CORE_EXPORT NGLogicalSize {
   NGLogicalSize() {}
   NGLogicalSize(LayoutUnit inline_size, LayoutUnit block_size)
       : inline_size(inline_size), block_size(block_size) {}
 
   LayoutUnit inline_size;
   LayoutUnit block_size;
 
   NGPhysicalSize ConvertToPhysical(NGWritingMode mode) const;
   bool operator==(const NGLogicalSize& other) const;
 
   bool IsEmpty() const {
     return inline_size == LayoutUnit() || block_size == LayoutUnit();
   }
 };
 
 CORE_EXPORT std::ostream& operator<<(std::ostream&, const NGLogicalSize&);
 
 }  // namespace blink
 
 #endif  // NGLogicalSize_h