Implement super initializers.

frog/leg/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.
 
 class WorkItem {
   final Element element;
   TreeElements resolutionTree;
   Function run;
   Map<int, BailoutInfo> bailouts = null;
 
@@ skipping 247 matching lines @@
       registerInstantiatedClass(element.enclosingElement);
     }
     worklist.add(new WorkItem.toCompile(element));
   }
 
   void registerStaticUse(Element element) {
     addToWorklist(element);
   }
 
   void registerDynamicInvocation(SourceString methodName, Selector selector) {
+    assert(selector !== null);
     Set<Invocation> existing = universe.invokedNames[methodName];
     if (existing == null) {
       universe.invokedNames[methodName] = new Set.from(<Selector>[selector]);
     } else {
       existing.add(selector);
     }
   }
 
   void registerDynamicGetter(SourceString methodName) {
     universe.invokedGetters.add(methodName);
@@ skipping 60 matching lines @@
 
 class CompilerCancelledException implements Exception {
   final String reason;
   CompilerCancelledException(this.reason);
 
   String toString() {
     String banner = 'compiler cancelled';
     return (reason !== null) ? '$banner: $reason' : '$banner';
   }
 }