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

third_party/WebKit/Source/core/layout/ng/NGUnits.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 NGUnits_h
-#define NGUnits_h
-
-namespace blink {
-
-class LayoutUnit;
-
-struct NGLogicalSize {
-    LayoutUnit inlineSize;
-    LayoutUnit blockSize;
-};
-
-struct NGLogicalOffset {
-    LayoutUnit inlineOffset;
-    LayoutUnit blockOffset;
-};
-
-struct NGPhysicalSize {
-    LayoutUnit width;
-    LayoutUnit height;
-};
-
-struct NGPhysicalLocation {
-    LayoutUnit top;
-    LayoutUnit left;
-};
-
-struct NGPhysicalRect {
-    NGPhysicalSize size;
-    NGPhysicalLocation location;
-};
-
-struct NGPixelSnappedPhysicalRect {
-    int top;
-    int left;
-    int width;
-    int height;
-};
-
-} // namespace blink
-
-#endif // NGUnits_h