Move nativeInfo encoding into NativeGenerator.

pkg/compiler/lib/src/js_emitter/model.dart

Index: pkg/compiler/lib/src/js_emitter/model.dart
diff --git a/pkg/compiler/lib/src/js_emitter/model.dart b/pkg/compiler/lib/src/js_emitter/model.dart
index b7e51bd3971110bb9c9d736b3e31cd203a429693..6b06eec99bf2e747ee4b4f3b554e36d341246818 100644
--- a/pkg/compiler/lib/src/js_emitter/model.dart
+++ b/pkg/compiler/lib/src/js_emitter/model.dart
@@ -243,8 +243,14 @@ class Class implements FieldContainer {
   /// Whether the class must be evaluated eagerly.
   bool isEager = false;
 
-  /// Data that must be emitted with the class for native interop.
-  js.Literal nativeInfo;
+  /// Leaf tags. See [NativeEmitter.prepareNativeClasses].
+  List<String> nativeLeafTags;
+
+  /// Non-leaf tags. See [NativeEmitter.prepareNativeClasses].
+  List<String> nativeNonLeafTags;
+
+  /// Native extensions. See [NativeEmitter.prepareNativeClasses].
+  List<Class> nativeExtensions;
 
   Class(this.element, this.name, this.holder,
         this.methods,