style: Add support for parsing container-query-specific features

There are some mediaqueries-5 features that we still don't support and
explain the remaining failures in at-container-{parsing,serialization}.

Differential Revision: https://phabricator.services.mozilla.com/D144446

components/style/queries/values.rs

@@ -0,0 +1,36 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! Common feature values between media and container features.
+
+/// The orientation media / container feature.
+/// https://drafts.csswg.org/mediaqueries-5/#orientation
+/// https://drafts.csswg.org/css-contain-3/#orientation
+#[derive(Clone, Copy, Debug, FromPrimitive, Parse, ToCss)]
+#[repr(u8)]
+#[allow(missing_docs)]
+pub enum Orientation {
+    Portrait,
+    Landscape,
+}
+
+impl Orientation {
+    /// A helper to evaluate a orientation query given a generic size getter.
+    pub fn eval<T>(size: euclid::default::Size2D<T>, value: Option<Self>) -> bool
+    where
+        T: PartialOrd,
+    {
+        let query_orientation = match value {
+            Some(v) => v,
+            None => return true,
+        };
+
+        // Per spec, square viewports should be 'portrait'
+        let is_landscape = size.width > size.height;
+        match query_orientation {
+            Self::Landscape => is_landscape,
+            Self::Portrait => !is_landscape,
+        }
+    }
+}