Web Animations CSS: Fix crash when animating viewport units

LayoutTests/animations/viewport-unit-crash.html

Index: LayoutTests/animations/viewport-unit-crash.html
diff --git a/LayoutTests/animations/viewport-unit-crash.html b/LayoutTests/animations/viewport-unit-crash.html
new file mode 100644
index 0000000000000000000000000000000000000000..c00b10a9e91b4735133d5dddcf958706eb465116
--- /dev/null
+++ b/LayoutTests/animations/viewport-unit-crash.html
@@ -0,0 +1,20 @@
+<style>
+@-webkit-keyframes test {
+  from { line-height: 25vw; }

[dstockwell, 2013/11/27 01:18:15]

Can we add cases that cover this to one of the interpolation/ tests?

[alancutter (OOO until 2018), 2013/11/27 04:55:25]

Done.

+  to { line-height: 50vh; }
+}
+#test {
+  -webkit-animation: test 1s;
+}
+</style>
+This tests animating viewport units. It passes if it doesn't crash.
+<div id="test"></div>
+<script>
+if (window.testRunner) {
+  testRunner.dumpAsText();
+  testRunner.waitUntilDone();
+  window.requestAnimationFrame(function() {
+    testRunner.notifyDone();
+  });
+}
+</script>