Update handling of ambiguous name references

runtime/vm/class_finalizer.cc

Index: runtime/vm/class_finalizer.cc
===================================================================
--- runtime/vm/class_finalizer.cc	(revision 27297)
+++ runtime/vm/class_finalizer.cc	(working copy)
@@ -259,23 +259,16 @@
   const String& class_name = String::Handle(unresolved_class.ident());
   Library& lib = Library::Handle();
   Class& resolved_class = Class::Handle();
-  String& ambiguity_error_msg = String::Handle();
   if (unresolved_class.library_prefix() == LibraryPrefix::null()) {
     lib = cls.library();
     ASSERT(!lib.IsNull());
-    resolved_class = lib.LookupClass(class_name, &ambiguity_error_msg);
+    resolved_class = lib.LookupClass(class_name);
   } else {
     LibraryPrefix& lib_prefix = LibraryPrefix::Handle();
     lib_prefix = unresolved_class.library_prefix();
     ASSERT(!lib_prefix.IsNull());
-    resolved_class = lib_prefix.LookupClass(class_name, &ambiguity_error_msg);
+    resolved_class = lib_prefix.LookupClass(class_name);
   }
-  if (resolved_class.IsNull() && !ambiguity_error_msg.IsNull()) {
-    const Script& script = Script::Handle(cls.script());
-    *ambiguity_error = Parser::FormatErrorMsg(
-        script, unresolved_class.token_pos(), "Error",
-        "%s", ambiguity_error_msg.ToCString());
-  }
   return resolved_class.raw();
 }