Incremental compilation: set up inheritance.

dart/pkg/dart2js_incremental/lib/library_updater.dart

 // Copyright (c) 2014, 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 dart2js_incremental.library_updater;
 
 import 'dart:async' show
     Future;
 
 import 'dart:convert' show
@@ skipping 399 matching lines @@
 
       // TODO(ahe): Compute statements, that is initializers.
       List<jsAst.Statement> statements = <jsAst.Statement>[];
 
       updates.add(
           js.statement(
               '# = function $name(#) {#}', [access, arguments, statements]));
     }
 
     for (ClassElementX cls in newClasses) {
-      // TODO(ahe): Set up superclasses.
+      if (cls.isObject) continue;
+      jsAst.Node classAccess = namer.elementAccess(cls);
+      jsAst.Node superAccess = namer.elementAccess(cls.superclass);
+
+      updates.add(
+          js.statement(
+              r'self.$dart_unsafe_eval.inheritFrom(#, #)',
+              [classAccess, superAccess]));
     }
 
     for (Element element in compiler.enqueuer.codegen.newlyEnqueuedElements) {
       if (!element.isField) {
         updates.add(computeMemberUpdateJs(element));
       }
     }
     for (RemovedFunctionUpdate update in removals) {
       update.writeUpdateJsOn(updates);
     }
@@ skipping 275 matching lines @@
 
 abstract class JsFeatures {
   Compiler get compiler;
 
   JavaScriptBackend get backend => compiler.backend;
 
   Namer get namer => backend.namer;
 
   CodeEmitterTask get emitter => backend.emitter;
 }