In background compilation make a copy of Field in order to freeze its state

runtime/vm/object_service.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/debugger.h"
 #include "vm/disassembler.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
@@ skipping 316 matching lines @@
 }
 
 
 void RedirectionData::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Object::PrintJSONImpl(stream, ref);
 }
 
 
 void Field::PrintJSONImpl(JSONStream* stream, bool ref) const {
   JSONObject jsobj(stream);
-  Class& cls = Class::Handle(owner());
+  Class& cls = Class::Handle(Owner());
   String& field_name = String::Handle(name());
   field_name = String::EncodeIRI(field_name);
   AddCommonObjectProperties(&jsobj, "Field", ref);
   jsobj.AddFixedServiceId("classes/%" Pd "/fields/%s",
                           cls.id(), field_name.ToCString());
 
   const String& user_name = String::Handle(UserVisibleName());
   const String& vm_name = String::Handle(name());
   AddNameProperties(&jsobj, user_name, vm_name);
   if (cls.IsTopLevel()) {
@@ skipping 27 matching lines @@
     cls ^= table->At(guarded_cid());
     jsobj.AddProperty("_guardClass", cls);
   }
   if (guarded_list_length() == kUnknownFixedLength) {
     jsobj.AddProperty("_guardLength", "unknown");
   } else if (guarded_list_length() == kNoFixedLength) {
     jsobj.AddProperty("_guardLength", "variable");
   } else {
     jsobj.AddProperty("_guardLength", guarded_list_length());
   }
-  const Class& origin_cls = Class::Handle(origin());
-  const Script& script = Script::Handle(origin_cls.script());
+  const Class& origin_cls = Class::Handle(Origin());
+  const class Script& script = Script::Handle(origin_cls.script());
   if (!script.IsNull()) {
     jsobj.AddLocation(script, token_pos());
   }
 }
 
 
 void LiteralToken::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Object::PrintJSONImpl(stream, ref);
 }
 
@@ skipping 1196 matching lines @@
   jsobj.AddProperty("mirrorReferent", referent_handle);
 }
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 #endif
 
 }  // namespace dart