Web Animations: Migrate SVG path interpolation to interpolation types

third_party/WebKit/LayoutTests/animations/svg-attribute-interpolation/resources/interpolation-test.js

Index: third_party/WebKit/LayoutTests/animations/svg-attribute-interpolation/resources/interpolation-test.js
diff --git a/third_party/WebKit/LayoutTests/animations/svg-attribute-interpolation/resources/interpolation-test.js b/third_party/WebKit/LayoutTests/animations/svg-attribute-interpolation/resources/interpolation-test.js
index fee72b2a7d703863d97d2c9353ed4296b7f3121b..16484d640eb8ca543516c262cecdeb3bbde6eff3 100644
--- a/third_party/WebKit/LayoutTests/animations/svg-attribute-interpolation/resources/interpolation-test.js
+++ b/third_party/WebKit/LayoutTests/animations/svg-attribute-interpolation/resources/interpolation-test.js
@@ -58,6 +58,9 @@
   }
 
   function normalizeValue(value) {
+    if (value === null) {
+      return '-NULL-';
+    }
     return roundNumbers(value).
         // Place whitespace between tokens.
         replace(/([\w\d.]+|[^\s])/g, '$1 ').
@@ -314,16 +317,22 @@
       case 'Web Animations':
         // Replace 'transform' with 'svgTransform', etc. This avoids collisions with CSS properties or the Web Animations API (offset).
         var prefixedProperty = 'svg' + params.property[0].toUpperCase() + params.property.slice(1);
-        target.animate([
-          {
+        var keyFrames = [];
+        if (params.from !== '') {
+          keyFrames.push({
+            offset: 0,
             [prefixedProperty]: params.from,
             composite: params.fromComposite,
-          },
-          {
+          })
+        }
+        if (params.to !== '') {
+          keyFrames.push({
+            offset: 1,
             [prefixedProperty]: params.to,
             composite: params.toComposite,
-          },
-        ], {
+          })
+        }
+        target.animate(keyFrames, {
           fill: 'forwards',
           duration: 1,
           easing: createEasing(expectation.at),