Add JavaScript AST.

lib/compiler/implementation/namer.dart

Index: lib/compiler/implementation/namer.dart
diff --git a/lib/compiler/implementation/namer.dart b/lib/compiler/implementation/namer.dart
index f9a21c82906bfdef084dbac10048590fe3b4b089..536de8f9266315487d132671baca6052a43def7b 100644
--- a/lib/compiler/implementation/namer.dart
+++ b/lib/compiler/implementation/namer.dart
@@ -44,6 +44,24 @@ class Namer {
                                         selector);
   }
 
+  String breakLabelName(LabelElement label) {
+    return '\$${label.labelName}\$${label.target.nestingLevel}';
+  }
+
+  String implicitBreakLabelName(TargetElement target) {
+    return '\$${target.nestingLevel}';
+  }
+
+  // We sometimes handle continue targets differently from break targets,
+  // so we have special continue-only labels.
+  String continueLabelName(LabelElement label) {
+    return 'c\$${label.labelName}\$${label.target.nestingLevel}';
+  }
+
+  String implicitContinueLabelName(TargetElement target) {
+    return 'c\$${target.nestingLevel}';
+  }
+
   /** Returns a non-unique name for the given closure element. */
   String closureName(Element element) {
     List<String> parts = <String>[];