Switch ddc to use @JS instead of @JSName

tool/input_sdk/private/annotations.dart

Index: tool/input_sdk/private/annotations.dart
diff --git a/tool/input_sdk/private/annotations.dart b/tool/input_sdk/private/annotations.dart
index 0e792eb8216cf3465e960e5a84d2f4d16ec04897..b7cc970ace3e42e3478ed72880e7959d125656ff 100644
--- a/tool/input_sdk/private/annotations.dart
+++ b/tool/input_sdk/private/annotations.dart
@@ -21,17 +21,6 @@ class Native {
   const Native(this.name);
 }
 
-// TODO(jmesserly): move these somewhere else, e.g. package:js or dart:js
-
-class JsName {
-  /// The JavaScript name.
-  /// Used for classes and libraries.
-  /// Note that this could be an expression, e.g. `lib.TypeName` in JS, but it
-  /// should be kept simple, as it will be generated directly into the code.
-  final String name;
-  const JsName({this.name});
-}
-
 class JsPeerInterface {
   /// The JavaScript type that we should match the API of.
   /// Used for classes where Dart subclasses should be callable from JavaScript