[LayoutNG] Implement atomic inlines for LayoutNGInline

third_party/WebKit/Source/core/layout/ng/ng_writing_mode.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 NGWritingMode_h
 #define NGWritingMode_h
 
 #include "core/CoreExport.h"
 #include "platform/text/WritingMode.h"
 
 namespace blink {
 
 enum NGWritingMode {
   kHorizontalTopBottom = 0,
   kVerticalRightLeft = 1,
   kVerticalLeftRight = 2,
   kSidewaysRightLeft = 3,
   kSidewaysLeftRight = 4
 };
 
 CORE_EXPORT NGWritingMode FromPlatformWritingMode(WritingMode);
 
+// Lines have horizontal orientation; modes horizontal-tb.
+inline bool IsHorizontalWritingMode(NGWritingMode writingMode) {
+  return writingMode == NGWritingMode::kHorizontalTopBottom;
+}
+
 // Whether the child and the containing block are parallel to each other.
 // Example: vertical-rl and vertical-lr
 bool IsParallelWritingMode(NGWritingMode a, NGWritingMode b);
 
 }  // namespace blink
 
 #endif  // NGWritingMode_h