Decouple LocalsHandler from Compiler and JavaScriptBackend

pkg/compiler/lib/src/ssa/graph_builder.dart

Index: pkg/compiler/lib/src/ssa/graph_builder.dart
diff --git a/pkg/compiler/lib/src/ssa/graph_builder.dart b/pkg/compiler/lib/src/ssa/graph_builder.dart
index a5e58bd28c7529268b518af8999840dea0d45636..5ea4133a75cb796a355eb3dd46fd11998c35e646 100644
--- a/pkg/compiler/lib/src/ssa/graph_builder.dart
+++ b/pkg/compiler/lib/src/ssa/graph_builder.dart
@@ -2,6 +2,7 @@
 // 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 '../closure.dart';
 import '../common/codegen.dart' show CodegenRegistry;
 import '../common_elements.dart';
 import '../compiler.dart';
@@ -57,6 +58,8 @@ abstract class GraphBuilder {
   GlobalTypeInferenceResults get globalInferenceResults =>
       compiler.globalInference.results;
 
+  ClosureTask get closureToClassMapper => compiler.closureToClassMapper;
+
   /// Used to track the locals while building the graph.
   LocalsHandler localsHandler;