Remove many features when building product mode

runtime/vm/scavenger.cc

Index: runtime/vm/scavenger.cc
diff --git a/runtime/vm/scavenger.cc b/runtime/vm/scavenger.cc
index 5dc0aae609ee1ac723c0c291b762ee94ef073035..bcbb79fed277ad6b27f8bd696e31a73892e22447 100644
--- a/runtime/vm/scavenger.cc
+++ b/runtime/vm/scavenger.cc
@@ -546,6 +546,9 @@ void Scavenger::IterateStoreBuffers(Isolate* isolate,
 
 void Scavenger::IterateObjectIdTable(Isolate* isolate,
                                      ScavengerVisitor* visitor) {
+  if (!FLAG_support_service) {
+    return;
+  }
   ObjectIdRing* ring = isolate->object_id_ring();
   if (ring == NULL) {
     // --gc_at_alloc can get us here before the ring has been initialized.
@@ -834,6 +837,9 @@ void Scavenger::WriteProtect(bool read_only) {
 
 
 void Scavenger::PrintToJSONObject(JSONObject* object) const {
+  if (!FLAG_support_service) {
+    return;
+  }
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL);
   JSONObject space(object, "new");