Ensure supertypes are loaded safely.

dart/lib/compiler/implementation/enqueue.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.
 
 class EnqueueTask extends CompilerTask {
   final Enqueuer codegen;
   final Enqueuer resolution;
 
   String get name() => 'Enqueue';
 
@@ skipping 196 matching lines @@
         return addToWorkList(member);
       }
     }
   }
 
   void onRegisterInstantiatedClass(ClassElement cls) {
     task.measure(() {
       while (cls !== null) {
         if (seenClasses.contains(cls)) return;
         seenClasses.add(cls);
-        // TODO(ahe): Don't call resolveType, instead, call this method
-        // when resolveType is called.
-        compiler.resolveClass(cls);
+        cls.ensureResolved(compiler);
         cls.members.forEach(processInstantiatedClassMember);
         cls = cls.superclass;
       }
     });
   }
 
   void registerNewSelector(SourceString name,
                            Selector selector,
                            Map<SourceString, Set<Selector>> selectorsMap) {
     Set<Selector> selectors =
@@ skipping 94 matching lines @@
   void forEach(f(WorkItem work)) {
     while (!queue.isEmpty()) {
       do {
         f(queue.removeLast());
       } while (!queue.isEmpty());
       // TODO(ahe): we shouldn't register the field closure invocations here.
       registerFieldClosureInvocations();
     }
   }
 }