Update material design icons

sky/sdk/lib/mojo/net/image_cache.dart

Index: sky/sdk/lib/mojo/net/image_cache.dart
diff --git a/sky/sdk/lib/mojo/net/image_cache.dart b/sky/sdk/lib/mojo/net/image_cache.dart
index b66d5fe67fcb92013db8cc1f3c396aa409a4aca2..9c71ea8fa7910df98f67ffceb4d91ac45fb61a79 100644
--- a/sky/sdk/lib/mojo/net/image_cache.dart
+++ b/sky/sdk/lib/mojo/net/image_cache.dart
@@ -18,6 +18,7 @@ Future<sky.Image> load(String url) {
     Completer<sky.Image> completer = new Completer<sky.Image>();
     fetchUrl(url).then((UrlResponse response) {
       if (response.statusCode >= 400) {
+        print("Failed to load image ${url}");
         completer.complete(null);
       } else {
         new sky.ImageDecoder(response.body.handle.h, completer.complete);