Generate needed classes for constant maps in metadata.

sdk/lib/_internal/compiler/implementation/resolution/members.dart

Index: sdk/lib/_internal/compiler/implementation/resolution/members.dart
diff --git a/sdk/lib/_internal/compiler/implementation/resolution/members.dart b/sdk/lib/_internal/compiler/implementation/resolution/members.dart
index 8b7644a457f441a2c1dceec56ac70a9e4f81db55..4075015e1c128e5cf2cc91d80c980921f7e19f09 100644
--- a/sdk/lib/_internal/compiler/implementation/resolution/members.dart
+++ b/sdk/lib/_internal/compiler/implementation/resolution/members.dart
@@ -1407,7 +1407,7 @@ class ResolverTask extends CompilerTask {
       // and the annotated element instead. This will allow the backend to
       // retrieve the backend constant and only register metadata on the
       // elements for which it is needed. (Issue 17732).
-      registry.registerMetadataConstant(annotation.value, annotatedElement);
+      registry.registerMetadataConstant(annotation, annotatedElement);
       annotation.resolutionState = STATE_DONE;
     }));
   }