Web Animations CSS: Fix crash when animating viewport units

LayoutTests/animations/interpolation/line-height-interpolation.html

Index: LayoutTests/animations/interpolation/line-height-interpolation.html
diff --git a/LayoutTests/animations/interpolation/line-height-interpolation.html b/LayoutTests/animations/interpolation/line-height-interpolation.html
index f29fb946fe579f485ea3e1c6579640701cfbd84d..6e592673091603177f12f566394b01d4c1180f6c 100644
--- a/LayoutTests/animations/interpolation/line-height-interpolation.html
+++ b/LayoutTests/animations/interpolation/line-height-interpolation.html
@@ -128,5 +128,61 @@ assertInterpolation({
   {at: 1, is: '4'},
   {at: 1.5, is: '4'},
 ]);
+assertInterpolation({
+  property: 'line-height',
+  from: '4vw',
+  to: '14vw'
+}, [
+  {at: -1, is: '0'},
+  {at: -0.3, is: '1vw'},
+  {at: 0, is: '4vw'},
+  {at: 0.3, is: '7vw'},
+  {at: 0.6, is: '10vw'},
+  {at: 1, is: '14vw'},
+  {at: 1.5, is: '19vw'},
+]);
+// content_shell --dump-render-tree uses a viewport of 800x600.
+assertInterpolation({
+  property: 'line-height',
+  from: '50vmin',
+  to: '100px'
+}, [
+  {at: -0.25, is: '350px'},
+  {at: 0, is: '300px'},
+  {at: 0.25, is: '250px'},
+  {at: 0.75, is: '150px'},
+  {at: 1, is: '100px'},
+  {at: 1.5, is: '0px'},
+]);
+assertInterpolation({
+  property: 'line-height',
+  from: '100px',
+  to: '50vmax'
+}, [
+  {at: -0.25, is: '25px'},
+  {at: 0, is: '100px'},
+  {at: 0.25, is: '175px'},
+  {at: 0.75, is: '325px'},
+  {at: 1, is: '400px'},
+  {at: 1.5, is: '550px'},
+]);
+assertInterpolation({
+  property: 'line-height',
+  from: '75vw',
+  to: '25vh'
+}, [
+  {at: -0.25, is: '712.5px'},
+  {at: 0, is: '600px'},
+  {at: 0.25, is: '487.5px'},
+  {at: 0.75, is: '262.5px'},
+  {at: 1, is: '150px'},
+  {at: 1.5, is: '0px'}, // line-height must not be less than 0.
+]);
 </script>
 </body>
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