Removed const from classes arrays in Observatory

runtime/observatory/lib/src/elements/retaining_path.dart

Index: runtime/observatory/lib/src/elements/retaining_path.dart
diff --git a/runtime/observatory/lib/src/elements/retaining_path.dart b/runtime/observatory/lib/src/elements/retaining_path.dart
index b0f2ea026179d420c6ee20be3074304ca9596051..2fb51ad806a098a337714da99cb1ab249ad42556 100644
--- a/runtime/observatory/lib/src/elements/retaining_path.dart
+++ b/runtime/observatory/lib/src/elements/retaining_path.dart
@@ -121,6 +121,7 @@ class RetainingPathElement extends HtmlElement implements Renderable {
       anyRef(_isolate, item.source, _instances, queue: _r.queue)
     );
 
-    return new DivElement()..classes = ['indent']..children = content;
+    return new DivElement()..classes = ['indent']
+            ..children = content;
   }
 }