Merge the Sky Engine changes from the SkyDart branch

sky/tests/resources/dump-as-render-tree.sky

Index: sky/tests/resources/dump-as-render-tree.sky
diff --git a/sky/tests/resources/dump-as-render-tree.sky b/sky/tests/resources/dump-as-render-tree.sky
index 1559d09bae57e0305ea07c4a60fbcddd3e93fd4f..0ea5f0399787c3524eb306136a82115c245d59ea 100644
--- a/sky/tests/resources/dump-as-render-tree.sky
+++ b/sky/tests/resources/dump-as-render-tree.sky
@@ -1,5 +1,9 @@
 <script>
-window.addEventListener('load', function() {
-  internals.notifyTestComplete(internals.renderTreeAsText());
-});
+import "dart:sky" as sky;
+import "dart:sky.internals" as internals;
+
+void init() {
+  sky.window.addEventListener('load', (_) =>
+    internals.notifyTestComplete(internals.renderTreeAsText()));  
+}
 </script>