dart2js: Use an abstract Name class for names in the generated JavaScript ast.

pkg/compiler/lib/src/js_backend/constant_emitter.dart

Index: pkg/compiler/lib/src/js_backend/constant_emitter.dart
diff --git a/pkg/compiler/lib/src/js_backend/constant_emitter.dart b/pkg/compiler/lib/src/js_backend/constant_emitter.dart
index f889a942a74ca98209c0419cec1ee11d858c6c16..3f38a2899a048e1bdb715181ca9c3d259e67f338 100644
--- a/pkg/compiler/lib/src/js_backend/constant_emitter.dart
+++ b/pkg/compiler/lib/src/js_backend/constant_emitter.dart
@@ -6,6 +6,8 @@ part of js_backend;
 
 typedef jsAst.Expression _ConstantReferenceGenerator(ConstantValue constant);
 
+typedef jsAst.Expression _ConstantListGenerator(jsAst.Expression array);
+
 /**
  * Generates the JavaScript expressions for constants.
  *
@@ -24,7 +26,7 @@ class ConstantEmitter
   final Compiler compiler;
   final Namer namer;
   final _ConstantReferenceGenerator constantReferenceGenerator;
-  final jsAst.Template makeConstantListTemplate;
+  final _ConstantListGenerator makeConstantList;
 
   /**
    * The given [constantReferenceGenerator] function must, when invoked with a
@@ -35,7 +37,7 @@ class ConstantEmitter
       this.compiler,
       this.namer,
       jsAst.Expression this.constantReferenceGenerator(ConstantValue constant),
-      this.makeConstantListTemplate);
+      this.makeConstantList);
 
   /**
    * Constructs a literal expression that evaluates to the constant. Uses a
@@ -160,7 +162,7 @@ class ConstantEmitter
         .map(constantReferenceGenerator)
         .toList(growable: false);
     jsAst.ArrayInitializer array = new jsAst.ArrayInitializer(elements);
-    jsAst.Expression value = makeConstantListTemplate.instantiate([array]);
+    jsAst.Expression value = makeConstantList(array);
     return maybeAddTypeArguments(constant.type, value);
   }
 
@@ -250,10 +252,9 @@ class ConstantEmitter
   @override
   jsAst.Expression visitType(TypeConstantValue constant, [_]) {
     DartType type = constant.representedType;
-    String name = namer.runtimeTypeName(type.element);
-    jsAst.Expression typeName = new jsAst.LiteralString("'$name'");
+    jsAst.Name typeName = namer.runtimeTypeName(type.element);
     return new jsAst.Call(getHelperProperty(backend.getCreateRuntimeType()),
-                          [typeName]);
+                          [js.quoteName(typeName)]);
   }
 
   @override
@@ -269,6 +270,7 @@ class ConstantEmitter
       case SyntheticConstantKind.EMPTY_VALUE:
         return new jsAst.LiteralNumber('0');
       case SyntheticConstantKind.TYPEVARIABLE_REFERENCE:
+      case SyntheticConstantKind.NAME:
         return constant.payload;
       default:
         compiler.internalError(NO_LOCATION_SPANNABLE,