Create a Tree IR builder for JavaScript specific nodes.

pkg/compiler/lib/src/dart_backend/backend.dart

Index: pkg/compiler/lib/src/dart_backend/backend.dart
diff --git a/pkg/compiler/lib/src/dart_backend/backend.dart b/pkg/compiler/lib/src/dart_backend/backend.dart
index 2c8dd77094ee5ea6cf53a99b677e6bcc1d984c5e..a1aaa46641e0d798af21d2eb3fd7717edaa36111 100644
--- a/pkg/compiler/lib/src/dart_backend/backend.dart
+++ b/pkg/compiler/lib/src/dart_backend/backend.dart
@@ -163,7 +163,7 @@ class DartBackend extends Backend {
     new cps_ir.RegisterAllocator().visit(cpsDefinition);
 
     tree_builder.Builder builder = new tree_builder.Builder(
-        new Glue(compiler), compiler.internalError, compiler.identicalFunction);
+        compiler.internalError, compiler.identicalFunction);
     tree_ir.ExecutableDefinition treeDefinition = builder.build(cpsDefinition);
     assert(treeDefinition != null);
     traceGraph('Tree builder', treeDefinition);