Make Icon work using space-aged base-url technology.

sky/sdk/lib/framework/components2/icon.dart

Index: sky/sdk/lib/framework/components2/icon.dart
diff --git a/sky/sdk/lib/framework/components2/icon.dart b/sky/sdk/lib/framework/components2/icon.dart
index 85b957f2b95a51dd9be30b4b08537a521394be60..2d31def83599133d7d3703c400acf1afe4463143 100644
--- a/sky/sdk/lib/framework/components2/icon.dart
+++ b/sky/sdk/lib/framework/components2/icon.dart
@@ -10,7 +10,7 @@ import '../rendering/box.dart';
 const String kAssetBase = '/packages/sky/assets/material-design-icons';
 
 class Icon extends Component {
-  double size;
+  int size;
   String type;
 
   Icon({
@@ -28,7 +28,7 @@ class Icon extends Component {
       subtype = parts[1];
     }
     return new Image(
-      size: new sky.Size(size, size),
+      size: new sky.Size(size.toDouble(), size.toDouble()),
       src: '${kAssetBase}/${category}/2x_web/ic_${subtype}_${size}dp.png'
     );
   }