Add expandable instances and lists to the vm service.

runtime/vm/json_stream.cc

Index: runtime/vm/json_stream.cc
diff --git a/runtime/vm/json_stream.cc b/runtime/vm/json_stream.cc
index 8dd4a01915e76c6af8a26b6658f64043b91b84d9..42cff75cf011ad99d6f3bb27e9bea6523aaaa7b7 100644
--- a/runtime/vm/json_stream.cc
+++ b/runtime/vm/json_stream.cc
@@ -127,14 +127,6 @@ void JSONStream::PrintValue(const Object& o, bool ref) {
 }
 
 
-void JSONStream::PrintValue(const Field& field,
-                            const Instance& instance,
-                            bool ref) {
-  PrintCommaIfNeeded();
-  field.PrintToJSONStreamWithInstance(this, instance, ref);
-}
-
-
 void JSONStream::PrintValue(SourceBreakpoint* bpt) {
   PrintCommaIfNeeded();
   bpt->PrintToJSONStream(this);