Implement subtype relation for kernel based elements.

pkg/compiler/lib/src/resolution/registry.dart

Index: pkg/compiler/lib/src/resolution/registry.dart
diff --git a/pkg/compiler/lib/src/resolution/registry.dart b/pkg/compiler/lib/src/resolution/registry.dart
index df2f729eb0657e4a67941e2a3fc50dc471311f50..cc9db2c00894e5e5bd57d51d3fa77e9682bc95e1 100644
--- a/pkg/compiler/lib/src/resolution/registry.dart
+++ b/pkg/compiler/lib/src/resolution/registry.dart
@@ -147,6 +147,12 @@ class ResolutionWorldImpactBuilder extends WorldImpactBuilderImpl
     if (_constSymbolNames != null) {
       sb.write('\n const-symbol-names: $_constSymbolNames');
     }
+    if (_nativeData != null) {
+      sb.write('\n native-data:');
+      for (var data in _nativeData) {
+        sb.write('\n  $data');
+      }
+    }
     return sb.toString();
   }
 }