[LayoutNG] Implement atomic inlines for LayoutNGInline

third_party/WebKit/Source/core/layout/ng/ng_writing_mode.h

Index: third_party/WebKit/Source/core/layout/ng/ng_writing_mode.h
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_writing_mode.h b/third_party/WebKit/Source/core/layout/ng/ng_writing_mode.h
index 18b9108621b60da3e250dab6e35448a745512ee9..da32800a6e33a226219e540fd98cf36a4dea67da 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_writing_mode.h
+++ b/third_party/WebKit/Source/core/layout/ng/ng_writing_mode.h
@@ -20,6 +20,11 @@ enum NGWritingMode {
 
 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);