Revert "Remove JavaScriptBackend from ClosedWorldBase"

pkg/compiler/lib/src/ssa/codegen_helpers.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.
 
 import '../constants/values.dart';
 import '../elements/elements.dart';
 import '../js_backend/js_backend.dart';
 import '../js_backend/interceptor_data.dart';
 import '../options.dart';
 import '../types/types.dart';
@@ skipping 124 matching lines @@
     // TODO(15933): Make automatically generated property extraction closures
     // work with the dummy receiver optimization.
     if (selector.isGetter) return;
 
     // This assignment of inputs is uniform for HInvokeDynamic and HInvokeSuper.
     HInstruction interceptor = node.inputs[0];
     HInstruction receiverArgument = node.inputs[1];
 
     if (interceptor.nonCheck() == receiverArgument.nonCheck()) {
       if (_interceptorData.isInterceptedSelector(selector) &&
-          !_interceptorData.isInterceptedMixinSelector(
-              selector, mask, _closedWorld)) {
+          !_interceptorData.isInterceptedMixinSelector(selector, mask)) {
         ConstantValue constant = new SyntheticConstantValue(
             SyntheticConstantKind.DUMMY_INTERCEPTOR,
             receiverArgument.instructionType);
         HConstant dummy = graph.addConstant(constant, _closedWorld);
         receiverArgument.usedBy.remove(node);
         node.inputs[1] = dummy;
         dummy.usedBy.add(node);
       }
     }
   }
@@ skipping 644 matching lines @@
     }
 
     // If [thenInput] is defined in the first predecessor, then it is only used
     // by [phi] and can be generated at use site.
     if (identical(thenInput.block, end.predecessors[0])) {
       assert(thenInput.usedBy.length == 1);
       markAsGenerateAtUseSite(thenInput);
     }
   }
 }