Implement measurement using futures

client/tests/client/layout/GridLayoutDemo.dart

Index: client/tests/client/layout/GridLayoutDemo.dart
diff --git a/client/tests/client/layout/GridLayoutDemo.dart b/client/tests/client/layout/GridLayoutDemo.dart
index c931b2bdebcbdafdba5710d3f1402f75c48e9232..02adbc90b80f4f8c852e1bbf6888d7226a359e2a 100644
--- a/client/tests/client/layout/GridLayoutDemo.dart
+++ b/client/tests/client/layout/GridLayoutDemo.dart
@@ -110,15 +110,21 @@ void printMetrics(String example) {
   for (Element child in node.elements) {
     _appendMetrics(sb, child, '    ');
   }
-  sb.add('  });\n');
-  sb.add('});\n\n');
-  window.console.log(sb.toString());
+  window.requestLayoutFrame(() {

[arv (Not doing code reviews), 2011/10/27 05:50:24]

This is the first case where this is feeling ugly.

It might actually be cleaner if a Future<List<Rect>> was used here.

[Jacob, 2011/10/27 20:59:25]

Agreed. I felt dirty writing that test code.
Rewrote using a List<Future<Rect>> so it is a bit more verbose but less
dependent on futures being resolved in exactly the order they were requested.

+    sb.add('  });\n');
+    sb.add('});\n\n');
+    window.console.log(sb.toString());
+  });
 }
 
 void _appendMetrics(StringBuffer sb, Element node, [String indent = '']) {
   String id = node.id;
-  num left = node.offsetLeft, top = node.offsetTop;
-  num width = node.offsetWidth, height = node.offsetHeight;
-  sb.add("${indent}'$id': [$left, $top, $width, $height],\n");
+  node.rect.then((rect) {
+    final offset = rect.offset;
+    num left = offset.left, top = offset.top;
+    num width = offset.width, height = offset.height;
+
+    sb.add("${indent}'$id': [$left, $top, $width, $height],\n");
+  });
 }