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

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, 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 "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "lib/stacktrace.h"
@@ skipping 4301 matching lines @@
           CURRENT_FUNC);
     }
     field = lib.LookupFieldAllowPrivate(field_name);
     if (field.IsNull()) {
       // No field found and no ambiguity error.  Check for a getter in the lib.
       const String& getter_name =
           String::Handle(Z, Field::GetterName(field_name));
       getter = lib.LookupFunctionAllowPrivate(getter_name);
     } else if (!field.IsNull() && field.IsUninitialized()) {
       // A field was found.  Check for a getter in the field's owner classs.
-      const Class& cls = Class::Handle(Z, field.owner());
+      const Class& cls = Class::Handle(Z, field.Owner());
       const String& getter_name = String::Handle(Z,
           Field::GetterName(field_name));
       getter = cls.LookupStaticFunctionAllowPrivate(getter_name);
     }
 
     if (!getter.IsNull()) {
       // Invoke the getter and return the result.
       return Api::NewHandle(
           T, DartEntry::InvokeFunction(getter, Object::empty_array()));
     }
@@ skipping 1833 matching lines @@
   return Api::Success();
 }
 #endif  // DART_PRECOMPILER
 
 
 DART_EXPORT bool Dart_IsRunningPrecompiledCode() {
   return Dart::IsRunningPrecompiledCode();
 }
 
 }  // namespace dart