Merge kernel closure conversion into the Dart SDK

pkg/kernel/lib/transformations/closure_conversion.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.transformations.closure_conversion;
+
+import '../ast.dart' show Class, Program;
+
+import '../core_types.dart' show CoreTypes;
+
+import 'closure/converter.dart' show ClosureConverter;
+
+import 'closure/info.dart' show ClosureInfo;
+
+import 'closure/mock.dart' show mockUpContext;
+
+Program transformProgram(Program program) {
+  var info = new ClosureInfo();
+  info.visitProgram(program);
+
+  CoreTypes coreTypes = new CoreTypes(program);
+  Class contextClass = mockUpContext(coreTypes, program);
+  var convert = new ClosureConverter(coreTypes, info, contextClass);
+  return convert.visitProgram(program);
+}