fast-startup: do not emit inherit calls for classes from different fragments

pkg/compiler/lib/src/js_emitter/startup_emitter/fragment_emitter.dart

 // Copyright (c) 2015, 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.js_emitter.startup_emitter.model_emitter;
 
 /// The name of the property that stores the tear-off getter on a static
 /// function.
 ///
 /// This property is only used when isolates are used.
@@ skipping 776 matching lines @@
   }
 
   /// Emits the inheritance block of the fragment.
   ///
   /// In this section prototype chains are updated and mixin functions are
   /// copied.
   js.Statement emitInheritance(Fragment fragment) {
     List<js.Expression> inheritCalls = <js.Expression>[];
     List<js.Expression> mixinCalls = <js.Expression>[];
 
+    Set<Class> classesInFragment = new Set<Class>();
+    for (Library library in fragment.libraries) {
+      classesInFragment.addAll(library.classes);
+    }
+
     Set<Class> emittedClasses = new Set<Class>();
 
     void emitInheritanceForClass(cls) {
       if (cls == null || emittedClasses.contains(cls)) return;
 
       Class superclass = cls.superclass;
-      emitInheritanceForClass(superclass);
+      if (classesInFragment.contains(superclass)) {
+        emitInheritanceForClass(superclass);
+      }
 
       js.Expression superclassReference = (superclass == null)
           ? new js.LiteralNull()
           : classReference(superclass);
 
       inheritCalls.add(
           js.js('inherit(#, #)', [classReference(cls), superclassReference]));
 
       emittedClasses.add(cls);
     }
@@ skipping 527 matching lines @@
     }
     statements.add(js.js.statement("setOrUpdateInterceptorsByTag(#);",
         js.objectLiteral(interceptorsByTag)));
     statements.add(
         js.js.statement("setOrUpdateLeafTags(#);", js.objectLiteral(leafTags)));
     statements.add(subclassAssignment);
 
     return new js.Block(statements);
   }
 }