Address review comments in commited cl (issue 10460002).

runtime/vm/flow_graph_builder.cc

 // Copyright (c) 2012, 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/flow_graph_builder.h"
 
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/code_descriptors.h"
 #include "vm/dart_entry.h"
@@ skipping 1308 matching lines @@
       function.set_context_scope(context_scope);
     }
   } else if (function.IsImplicitInstanceClosureFunction()) {
     ValueGraphVisitor for_receiver(owner(), temp_index());
     node->receiver()->Visit(&for_receiver);
     Append(for_receiver);
   }
   ASSERT(function.context_scope() != ContextScope::null());
 
   // The function type of a closure may have type arguments. In that case, pass
-  // the type arguments of the instantiator.
+  // the type arguments of the instantiator. Otherwise, pass null object.
   const Class& cls = Class::Handle(function.signature_class());
   ASSERT(!cls.IsNull());
   const bool requires_type_arguments = cls.HasTypeArguments();
   Value* type_arguments = NULL;
   if (requires_type_arguments) {
     ASSERT(!function.IsImplicitStaticClosureFunction());
     type_arguments = BuildInstantiatorTypeArguments(node->token_index(), NULL);
+  } else {
+    type_arguments = BuildNullValue();
   }
 
   CreateClosureComp* create =
       new CreateClosureComp(node, owner()->try_index(), type_arguments);
   ReturnComputation(create);
 }
 
 
 void EffectGraphVisitor::TranslateArgumentList(
     const ArgumentListNode& node,
@@ skipping 1089 matching lines @@
   char* chars = reinterpret_cast<char*>(
       Isolate::Current()->current_zone()->Allocate(len));
   OS::SNPrint(chars, len, kFormat, function_name, reason);
   const Error& error = Error::Handle(
       LanguageError::New(String::Handle(String::New(chars))));
   Isolate::Current()->long_jump_base()->Jump(1, error);
 }
 
 
 }  // namespace dart