Implement reflecting on uninstantiated classes.

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

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart2js;
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
@@ skipping 505 matching lines @@
     tasks.addAll(backend.tasks);
     metadataHandler = new ConstantHandler(
         this, backend.constantSystem, isMetadata: true);
   }
 
   Universe get resolverWorld => enqueuer.resolution.universe;
   Universe get codegenWorld => enqueuer.codegen.universe;
 
   bool get hasBuildId => buildId != UNDETERMINED_BUILD_ID;
 
+  bool get mirrorsEnabled => mirrorSystemClass != null;
+
   int getNextFreeClassId() => nextFreeClassId++;
 
   void ensure(bool condition) {
     if (!condition) cancel('failed assertion in leg');
   }
 
   void unimplemented(String methodName,
                      {Node node, Token token, HInstruction instruction,
                       Element element}) {
     internalError("$methodName not implemented",
@@ skipping 341 matching lines @@
 
     if (compilationFailed) return;
 
     backend.assembleProgram();
 
     checkQueues();
   }
 
   void resolveReflectiveDataIfNeeded() {
     // Only need reflective data when dart:mirrors is loaded.
-    if (mirrorSystemClass == null) return;
+    if (!mirrorsEnabled) return;
 
     for (LibraryElement library in libraries.values) {
       for (Link link = library.metadata; !link.isEmpty; link = link.tail) {
         link.head.ensureResolved(this);
       }
     }
   }
 
   void fullyEnqueueLibrary(LibraryElement library) {
     library.implementation.forEachLocalMember(fullyEnqueueTopLevelElement);
@@ skipping 463 matching lines @@
 
   void close() {}
 
   toString() => name;
 
   /// Convenience method for getting an [api.CompilerOutputProvider].
   static NullSink outputProvider(String name, String extension) {
     return new NullSink('$name.$extension');
   }
 }