Add Observatory support for UnlinkedCall, SingleTargetCache and SubtypeTestCache.

runtime/vm/object_service.cc

Index: runtime/vm/object_service.cc
diff --git a/runtime/vm/object_service.cc b/runtime/vm/object_service.cc
index 8cf15a8b97a15203ee5f19a65f1d9cc233424655..fe9566c0f9859ce8fb6dcfb3e48b47627e1533ad 100644
--- a/runtime/vm/object_service.cc
+++ b/runtime/vm/object_service.cc
@@ -756,12 +756,27 @@ void ExceptionHandlers::PrintJSONImpl(JSONStream* stream, bool ref) const {
 
 
 void SingleTargetCache::PrintJSONImpl(JSONStream* stream, bool ref) const {
-  Object::PrintJSONImpl(stream, ref);
+  JSONObject jsobj(stream);
+  AddCommonObjectProperties(&jsobj, "Object", ref);
+  jsobj.AddServiceId(*this);
+  jsobj.AddProperty("_target", Code::Handle(target()));
+  if (ref) {
+    return;
+  }
+  jsobj.AddProperty("_lowerLimit", lower_limit());
+  jsobj.AddProperty("_upperLimit", upper_limit());
 }
 
 
 void UnlinkedCall::PrintJSONImpl(JSONStream* stream, bool ref) const {
-  Object::PrintJSONImpl(stream, ref);
+  JSONObject jsobj(stream);
+  AddCommonObjectProperties(&jsobj, "Object", ref);
+  jsobj.AddServiceId(*this);
+  jsobj.AddProperty("_selector", String::Handle(target_name()).ToCString());
+  if (ref) {
+    return;
+  }
+  jsobj.AddProperty("_argumentsDescriptor", Array::Handle(args_descriptor()));
 }
 
 
@@ -925,7 +940,13 @@ void MegamorphicCache::PrintJSONImpl(JSONStream* stream, bool ref) const {
 
 
 void SubtypeTestCache::PrintJSONImpl(JSONStream* stream, bool ref) const {
-  Object::PrintJSONImpl(stream, ref);
+  JSONObject jsobj(stream);
+  AddCommonObjectProperties(&jsobj, "Object", ref);
+  jsobj.AddServiceId(*this);
+  if (ref) {
+    return;
+  }
+  jsobj.AddProperty("_cache", Array::Handle(cache()));
 }