Refactor LoopHandler to avoid calling KernelAstAdapter.getNode

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

Index: pkg/compiler/lib/src/kernel/element_map.dart
diff --git a/pkg/compiler/lib/src/kernel/element_map.dart b/pkg/compiler/lib/src/kernel/element_map.dart
index 84904aeae9b21a98313bc63e61e8ec5d9a1f1373..7331674706b347ab903b3556660a4432e36e48fa 100644
--- a/pkg/compiler/lib/src/kernel/element_map.dart
+++ b/pkg/compiler/lib/src/kernel/element_map.dart
@@ -4,6 +4,7 @@
 
 import 'package:kernel/ast.dart' as ir;
 
+import '../closure.dart';
 import '../common.dart';
 import '../common/names.dart';
 import '../constants/constructors.dart';
@@ -1037,4 +1038,8 @@ abstract class KernelToLocalsMap {
   /// 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 [ClosureScope] for the loop [node] in [cloureData].
+  ClosureScope getClosureScopeForLoop(
+      ClosureClassMap closureData, ir.TreeNode node);
 }