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

sky/tests/lowlevel/bug-438036.sky

Index: sky/tests/lowlevel/bug-438036.sky
diff --git a/sky/tests/lowlevel/bug-438036.sky b/sky/tests/lowlevel/bug-438036.sky
index a92954aa8c13c427fbb1afa6d75dde04d240ad69..53f57514687a886ff9f417f5dee74f30aa68a208 100644
--- a/sky/tests/lowlevel/bug-438036.sky
+++ b/sky/tests/lowlevel/bug-438036.sky
@@ -19,7 +19,7 @@ void main() {
     var target = document.querySelector('div');
 
     target.classList.add("wide");
-    expect(window.getComputedStyle(target).getPropertyValue("width"),
+    expect(window.getComputedStyle(target)["width"],
            equals("200px"));
   });
 
@@ -27,7 +27,7 @@ void main() {
     var target = document.querySelectorAll('div')[1];
 
     target.setAttribute("id", "high");
-    expect(window.getComputedStyle(target).getPropertyValue("height"),
+    expect(window.getComputedStyle(target)["height"],
            equals("200px"));
   });
 }