Throw when reflecting on elements not covered by a `MirrorsUsed` annotation.

sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart b/sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart
index 965822ea6c0c54cf5ca4370ebb5b6f15ecb59839..ed09190b9bcfbd6bfbd2938ebcc40d99324a9b7f 100644
--- a/sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart
@@ -1269,7 +1269,7 @@ class CodeEmitterTask extends CompilerTask {
       code = extendWithMetadata(member, code);
       builder.addProperty(name, code);
       String reflectionName = getReflectionName(member, name);
-      if (reflectionName != null) {
+      if (reflectionName != null && backend.isAccessibleByReflection(member)) {

[ahe, 2013/08/26 20:41:15]

I thought we determined that not having a reflectionName isn't sufficient, and
that you planned to use lack of metadata.

         builder.addProperty('+$reflectionName', js('0'));
       }
       code = backend.generatedBailoutCode[member];
@@ -1982,7 +1982,8 @@ class CodeEmitterTask extends CompilerTask {
     }
     buffer.write('$className:$_');
     buffer.write(jsAst.prettyPrint(builder.toObjectInitializer(), compiler));
-    if (backend.shouldRetainName(classElement.name)) {
+    if (backend.shouldRetainName(classElement.name) &&
+        backend.isAccessibleByReflection(classElement)) {
       String reflectionName = getReflectionName(classElement, className);
       List<int> interfaces = <int>[];
       for (DartType interface in classElement.interfaces) {
@@ -2286,7 +2287,8 @@ class CodeEmitterTask extends CompilerTask {
       code = extendWithMetadata(element, code);
       emitStaticFunction(buffer, name, code);
       String reflectionName = getReflectionName(element, name);
-      if (reflectionName != null) {
+      if (reflectionName != null &&
+          backend.isAccessibleByReflection(element)) {
         buffer.write(',$n$n"+$reflectionName":${_}0');
       }
       jsAst.Expression bailoutCode = backend.generatedBailoutCode[element];