Implement VariableMirror creation with non-API code. To break circular initialization, have them fi…

runtime/vm/object.cc

Index: runtime/vm/object.cc
===================================================================
--- runtime/vm/object.cc	(revision 25253)
+++ runtime/vm/object.cc	(working copy)
@@ -14227,6 +14227,12 @@
 }
 
 
+RawField* MirrorReference::GetFieldReferent() const {
+  ASSERT(Object::Handle(referent()).IsField());
+  return Field::Cast(Object::Handle(referent())).raw();
+}
+
+
 RawFunction* MirrorReference::GetFunctionReferent() const {
   ASSERT(Object::Handle(referent()).IsFunction());
   return Function::Cast(Object::Handle(referent())).raw();