Preserve type variables in closure conversion.

pkg/kernel/lib/text/ast_to_text.dart

 // 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.
 library kernel.ast_to_text;
 
 import '../ast.dart';
 import '../import_table.dart';
 
 class Namer<T> {
   int index = 0;
@@ skipping 1043 matching lines @@
     writeWord('CopyVector');
     writeSymbol('(');
     writeExpression(node.vectorExpression);
     writeSymbol(')');
   }
 
   visitClosureCreation(ClosureCreation node) {
     writeWord('MakeClosure');
     writeSymbol('<');
     writeNode(node.functionType);
+    if (node.typeArgs.length > 0) writeSymbol(', ');
+    writeList(node.typeArgs, writeType);
     writeSymbol('>');
     writeSymbol('(');
     writeMemberReference(node.topLevelFunction);
     writeComma();
     writeExpression(node.contextVector);
     writeSymbol(')');
   }
 
   visitLibraryDependency(LibraryDependency node) {
     writeIndentation();
@@ skipping 594 matching lines @@
   }
   throw 'illegal ProcedureKind: $kind';
 }
 
 class ExpressionPrinter {
   final Printer writeer;
   final int minimumPrecedence;
 
   ExpressionPrinter(this.writeer, this.minimumPrecedence);
 }