[CSS Typed OM] Refactor is2D handling in CSSTransformComponents to match new spec

third_party/WebKit/LayoutTests/typedcssom/cssTranslation.html

Index: third_party/WebKit/LayoutTests/typedcssom/cssTranslation.html
diff --git a/third_party/WebKit/LayoutTests/typedcssom/cssTranslation.html b/third_party/WebKit/LayoutTests/typedcssom/cssTranslation.html
index d78160590d9866501073778b50bbc2ee3e7ee72d..5d8fe067c998c1a8115e0003f1e9eda0e2d0ab38 100644
--- a/third_party/WebKit/LayoutTests/typedcssom/cssTranslation.html
+++ b/third_party/WebKit/LayoutTests/typedcssom/cssTranslation.html
@@ -10,7 +10,7 @@ var negativeLength = new CSSUnitValue(-2.2, "em");
 var tenPercent = new CSSUnitValue(10, "percent");
 
 var testParams = [
-  // 2D CSSTranslation Transform Components
+  // 2D translations
   {
     input: new CSSTranslation(zeroLength, zeroLength),
     x: zeroLength, y: zeroLength,
@@ -29,7 +29,7 @@ var testParams = [
     is2D: true,
     cssText: "translate(10%, 0px)"
   },
-  // 3D CSSTranslation Transform Components
+  // 3D translations
   {
     input: new CSSTranslation(zeroLength, zeroLength, zeroLength),
     x: zeroLength, y: zeroLength, z: zeroLength,
@@ -55,14 +55,14 @@ for (let params of testParams) {
     assert_equals(params.input.x, params.x);
     assert_equals(params.input.y, params.y);
     if (params.is2D) {
-      assert_equals(params.input.z, null);
+      assert_equals(params.input.z.value, 0);
     } else {
       assert_equals(params.input.z, params.z);
     }
   }, "x, y, and z values are correct for " + params.cssText);
 
   test(() => {
-    assert_equals(params.input.is2D(), params.is2D);
+    assert_equals(params.input.is2D, params.is2D);
   }, "is2D value is correct for " + params.cssText);
 
   test(() => {
@@ -78,7 +78,7 @@ test(() => {
   assert_equals(translation.x.unit, 'percent');
   assert_equals(translation.y.value, 20);
   assert_equals(translation.y.unit, 'percent');
-  assert_equals(translation.z, null);
+  assert_equals(translation.z.value, 0);
 
   let translation3d = new CSSTranslation(
       new CSSUnitValue(30, 'percent'),