Make element.style["color"] work in Sky

sky/tests/layout/document-elementFromPoint.sky

Index: sky/tests/layout/document-elementFromPoint.sky
diff --git a/sky/tests/layout/document-elementFromPoint.sky b/sky/tests/layout/document-elementFromPoint.sky
index 68c0125b9fc100a2d62cbbcfbbbfb44c4a7a783d..461b782d0979c9e4cc34980d8c26fe6fa88261fd 100644
--- a/sky/tests/layout/document-elementFromPoint.sky
+++ b/sky/tests/layout/document-elementFromPoint.sky
@@ -47,12 +47,12 @@ void main() {
   });
 
   test("should hit test child with layered parent", () {
-    document.querySelector('parent').style.setProperty("transform", "translate3d(0, 0, 0)");
+    document.querySelector('parent').style["transform"] = "translate3d(0, 0, 0)";
     hitTestWithChildren();
   });
 
   test("should hit test transformed child", () {
-    document.querySelector('child').style.setProperty("transform", "translate3d(100px, 0, 0)");
+    document.querySelector('child').style["transform"] = "translate3d(100px, 0, 0)";
     expect(document.elementFromPoint(50, 210).tagName, equals('parent'));
     expect(document.elementFromPoint(150, 210).tagName, equals('child'));
   });