Start adding support for mixin application syntax. We now parse the typedef variant of mixin applic…

sdk/lib/_internal/compiler/implementation/dart_backend/utils.dart

Index: sdk/lib/_internal/compiler/implementation/dart_backend/utils.dart
diff --git a/sdk/lib/_internal/compiler/implementation/dart_backend/utils.dart b/sdk/lib/_internal/compiler/implementation/dart_backend/utils.dart
index 4c4547d72617a7b40080914d47fa70122faca123..e456222f30bd643743113426b716eb5c3ccd0e0c 100644
--- a/sdk/lib/_internal/compiler/implementation/dart_backend/utils.dart
+++ b/sdk/lib/_internal/compiler/implementation/dart_backend/utils.dart
@@ -117,6 +117,10 @@ class CloningVisitor implements Visitor<Node> {
   visitLiteralString(LiteralString node) => new LiteralString(
       node.token, node.dartString);
 
+  visitMixinApplication(MixinApplication node) => new MixinApplication(
+      visit(node.modifiers), visit(node.superclass), visit(node.mixins),
+      node.beginToken, node.endToken);
+
   visitModifiers(Modifiers node) => new Modifiers(visit(node.nodes));
 
   visitNamedArgument(NamedArgument node) => new NamedArgument(