servo: Merge #18078 - Make vertical-align animatable between percentage and percentage or l… (from hiikezoe:vertical-align-animation); r=boris

…ength.

<!-- Please describe your changes on the following line: -->
https://bugzilla.mozilla.org/show_bug.cgi?id=1387949

---
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors

Source-Repo: https://github.com/servo/servo
Source-Revision: 0aba7442a6e59084762ecd49889c33457a90917b

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 6ededdf1ba11fce5b6a1e965b0c295237f3af524

servo/components/style/properties/helpers/animated_properties.mako.rs

@@ -943,10 +943,10 @@ impl Animatable for VerticalAlign {
     #[inline]
     fn add_weighted(&self, other: &Self, self_portion: f64, other_portion: f64) -> Result<Self, ()> {
         match (*self, *other) {
-            (VerticalAlign::LengthOrPercentage(LengthOrPercentage::Length(ref this)),
-             VerticalAlign::LengthOrPercentage(LengthOrPercentage::Length(ref other))) => {
+            (VerticalAlign::LengthOrPercentage(ref this),
+             VerticalAlign::LengthOrPercentage(ref other)) => {
                 this.add_weighted(other, self_portion, other_portion).map(|value| {
-                    VerticalAlign::LengthOrPercentage(LengthOrPercentage::Length(value))
+                    VerticalAlign::LengthOrPercentage(value)
                 })
             }
             _ => Err(()),