Refactor LoopHandler to avoid calling KernelAstAdapter.getNode

pkg/compiler/lib/src/kernel/element_map.dart

 // Copyright (c) 2017, 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.
 
 import 'package:kernel/ast.dart' as ir;
 
+import '../closure.dart';
 import '../common.dart';
 import '../common/names.dart';
 import '../constants/constructors.dart';
 import '../constants/expressions.dart';
 import '../constants/values.dart';
 import '../common_elements.dart';
 import '../elements/elements.dart' show JumpTarget;
 import '../elements/entities.dart';
 import '../elements/names.dart';
 import '../elements/operators.dart';
@@ skipping 1013 matching lines @@
 
   /// Call to notify that [member] is no longer being inlined.
   void leaveInlinedMember(MemberEntity member);
 
   /// Returns the [Local] for [node].
   Local getLocal(ir.VariableDeclaration node);
 
   /// Returns the [JumpTarget] for the branch in [node].
   // TODO(johnniwinther): Split this by kind of [node]?
   JumpTarget getJumpTarget(ir.TreeNode node, {bool isContinueTarget: false});
+
+  /// Returns the [LoopClosureRepresentationInfo] for the loop [node] in
+  /// [closureClassMaps].
+  LoopClosureRepresentationInfo getClosureRepresentationInfoForLoop(
+      ClosureClassMaps closureClassMaps, ir.TreeNode node);
 }