dart2dart: Introduce Renamer that is used by renaming unparser

lib/compiler/implementation/dart_backend/renaming_unparser.dart

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// 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.
+
+class RenamingUnparser extends Unparser {

[Anton Muhin, 2012/07/23 11:23:10]

do we need both RenamingUnparser and Unparser?  I don't think so.

[Roman, 2012/07/23 15:34:15]

Merged.

+  final Renamer renamer;
+
+  RenamingUnparser(this.renamer);
+
+  visitSend(Send node) {
+    if (node.selector !== null && node.selector is TypeAnnotation) {

[Anton Muhin, 2012/07/23 11:23:10]

no need in !== check, null is TypeAnnotation should be false, if I remember it
right.

[Roman, 2012/07/23 15:34:15]

(null is AnyType) == true

+      super.visitSend(node);

[Anton Muhin, 2012/07/23 11:23:10]

return super.visitSend(node)?

+      return;
+    }
+    String newMethod = renamer.renameSendMethod(node);
+    if (newMethod !== null) {
+      sb.add(newMethod);
+      visit(node.argumentsNode);
+    } else {
+      super.visitSend(node);
+    }
+  }
+
+  visitTypeAnnotation(TypeAnnotation node) {
+    String newName = renamer.renameTypeName(node);
+    if (newName !== null) {
+      sb.add(newName);
+      visit(node.typeArguments);
+    } else {
+      super.visitTypeAnnotation(node);
+    }
+  }
+
+  visitIdentifier(Identifier node) {
+    String newName = renamer.renameIdentifier(node);
+    if (newName == null) {
+      super.visitIdentifier(node);
+    } else {
+      sb.add(newName);
+    }
+  }
+}