[LayoutNG] Change core/layout/ng to Chromium style and rename files.

third_party/WebKit/Source/core/layout/ng/ng_margin_strut.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 NGMarginStrut_h
 #define NGMarginStrut_h
 
 #include "core/CoreExport.h"
 #include "platform/LayoutUnit.h"
 
 namespace blink {
 
 // This struct is used for the margin collapsing calculation.
 struct NGMarginStrut {
-    LayoutUnit marginBlockStart;
-    LayoutUnit marginBlockEnd;
+  LayoutUnit marginBlockStart;
+  LayoutUnit marginBlockEnd;
 
-    LayoutUnit negativeMarginBlockStart;
-    LayoutUnit negativeMarginBlockEnd;
+  LayoutUnit negativeMarginBlockStart;
+  LayoutUnit negativeMarginBlockEnd;
 };
 
-} // namespace blink
+}  // namespace blink
 
-#endif // NGMarginStrut_h
+#endif  // NGMarginStrut_h