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..039b78b3da90781f5a4ca679ac34fc3c9e335d35 100644
--- a/LayoutTests/animations/interpolation/line-height-interpolation.html
+++ b/LayoutTests/animations/interpolation/line-height-interpolation.html
@@ -128,5 +128,54 @@ 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'},
+]);
+assertInterpolation({
+  property: 'line-height',
+  from: '50vmin',
+  to: '100px'
+}, [
+  {at: -0.25, is: '50vmin'},
+  {at: 0, is: '50vmin'},
+  {at: 0.25, is: '50vmin'},
+  {at: 0.75, is: '100px'},
+  {at: 1, is: '100px'},
+  {at: 1.5, is: '100px'},
+]);
+assertInterpolation({
+  property: 'line-height',
+  from: '100px',
+  to: '50vmax'
+}, [
+  {at: -0.25, is: '100px'},

[dstockwell, 2013/11/27 09:27:34]

This seems to suggest that stepping is the correct behavior? The values here
should represent what would be output if interpolation was correctly implemented
and the expectation should contain FAIL lines for now.

[alancutter (OOO until 2018), 2013/11/27 23:31:52]

Done.

+  {at: 0, is: '100px'},
+  {at: 0.25, is: '100px'},
+  {at: 0.75, is: '50vmax'},
+  {at: 1, is: '50vmax'},
+  {at: 1.5, is: '50vmax'},
+]);
+assertInterpolation({
+  property: 'line-height',
+  from: '50vw',
+  to: '100vh'
+}, [
+  {at: -0.25, is: '50vw'},
+  {at: 0, is: '50vw'},
+  {at: 0.25, is: '50vw'},
+  {at: 0.75, is: '100vh'},
+  {at: 1, is: '100vh'},
+  {at: 1.5, is: '100vh'},
+]);
 </script>
 </body>