Ensure interfaces are loaded.

dart/tests/compiler/dart2js/mock_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.
 
 #library('mock_compiler');
 
 #import("dart:uri");
 
 #import("../../../lib/compiler/implementation/elements/elements.dart");
 #import("../../../lib/compiler/implementation/leg.dart");
 #import('../../../lib/compiler/implementation/source_file.dart');
 #import("../../../lib/compiler/implementation/tree/tree.dart");
 #import("../../../lib/compiler/implementation/util/util.dart");
+#import('../../../lib/compiler/compiler.dart', prefix: 'api');
 #import("parser_helper.dart");
 
 class WarningMessage {
   Node node;
   Message message;
   WarningMessage(this.node, this.message);
 
   toString() => message.toString();
 }
 
@@ skipping 74 matching lines @@
   }
 
   void reportError(Node node, var message) {
     if (message is String && message.startsWith("no #library tag found in")) {
       // TODO(ahe): Fix the MockCompiler to not have this problem.
       return;
     }
     errors.add(new WarningMessage(node, message.message));
   }
 
+  void reportMessage(SourceSpan span, var message, api.Diagnostic kind) {
+    var diagnostic = new WarningMessage(null, message.message);
+    if (kind === api.Diagnostic.ERROR) {
+      errors.add(diagnostic);
+    } else {
+      warnings.add(diagnostic);
+    }
+  }
+
   void reportDiagnostic(SourceSpan span, String message, var kind) {
     print(message);
   }
 
   void clearWarnings() {
     warnings = [];
   }
 
   void clearErrors() {
     errors = [];
@@ skipping 79 matching lines @@
       });
   }
 }
 
 LibraryElement mockLibrary(Compiler compiler, String source) {
   Uri uri = new Uri.fromComponents(scheme: "source");
   var library = new LibraryElement(new Script(uri, new MockFile(source)));
   importLibrary(library, compiler.coreLibrary, compiler);
   return library;
 }