Remove Registry from registerMetadataConstant

tests/compiler/dart2js/mirrors_used_test.dart

Index: tests/compiler/dart2js/mirrors_used_test.dart
diff --git a/tests/compiler/dart2js/mirrors_used_test.dart b/tests/compiler/dart2js/mirrors_used_test.dart
index dffab8af88acd6885003a9e98d2c5f07a70efa44..fc08b6b82f9fb6e254c5f212c87736ba0b5e1f05 100644
--- a/tests/compiler/dart2js/mirrors_used_test.dart
+++ b/tests/compiler/dart2js/mirrors_used_test.dart
@@ -127,18 +127,22 @@ void main() {
       });
     }
 
-    // There should at least be one metadata constant:
-    // 1. The constructed constant for 'MirrorsUsed'.
-    Expect.isTrue(backend.metadataConstants.length >= 1);
-
+    int metadataCount = 0;
     Set<ConstantValue> compiledConstants = backend.constants.compiledConstants;
     // Make sure that most of the metadata constants aren't included in the
     // generated code.
-    for (var dependency in backend.metadataConstants) {
-      ConstantValue constant = dependency.constant;
+    backend.processMetadata(
+        compiler.enqueuer.resolution.processedElements, (metadata) {
+      ConstantValue constant =
+          backend.constants.getConstantValueForMetadata(metadata);
       Expect.isFalse(compiledConstants.contains(constant),
                      constant.toStructuredText());
-    }
+      metadataCount++;
+    });
+
+    // There should at least be one metadata constant:
+    // 1. The constructed constant for 'MirrorsUsed'.
+    Expect.isTrue(metadataCount >= 1);
 
     // The type literal 'Foo' is both used as metadata, and as a plain value in
     // the program. Make sure that it isn't duplicated.