From 35a98af0ed5bb99735a513911184036e1a15d9db Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Mon, 16 Sep 2019 09:22:44 +0900
Subject: [PATCH] style: Add a comment quoting the spec.

---
 components/style/logical_geometry.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/components/style/logical_geometry.rs b/components/style/logical_geometry.rs
index c1e01216d195..dd912da4af9d 100644
--- a/components/style/logical_geometry.rs
+++ b/components/style/logical_geometry.rs
@@ -140,6 +140,13 @@ impl WritingMode {
                         TextOrientation::Mixed => {},
                         TextOrientation::Upright => {
                             flags.insert(WritingMode::UPRIGHT);
+
+                            // https://drafts.csswg.org/css-writing-modes-3/#valdef-text-orientation-upright:
+                            //
+                            // > This value causes the used value of direction
+                            // > to be ltr, and for the purposes of bidi
+                            // > reordering, causes all characters to be treated
+                            // > as strong LTR.
                             flags.remove(WritingMode::RTL);
                             flags.remove(WritingMode::INLINE_REVERSED);
                         },