Merge CommonElements and BackendHelpers!

pkg/compiler/lib/src/js_emitter/parameter_stub_generator.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.
 
 library dart2js.js_emitter.parameter_stub_generator;
 
 import '../closure.dart' show ClosureClassElement;
 import '../common.dart';
 import '../compiler.dart' show Compiler;
 import '../constants/values.dart';
@@ skipping 199 matching lines @@
   // We need to pay attention if this stub is for a function that has been
   // invoked from a subclass. Then we cannot just redirect, since that
   // would invoke the methods of the subclass. We have to compile to:
   // (1) foo$2(a, b) => MyClass.foo$4$c$d.call(this, a, b, null, null)
   // (2) foo$3$c(a, b, c) => MyClass.foo$4$c$d(this, a, b, c, null);
   // (3) foo$3$d(a, b, d) => MyClass.foo$4$c$d(this, a, b, null, d);
   List<ParameterStubMethod> generateParameterStubs(MethodElement member,
       {bool canTearOff: true}) {
     if (member.enclosingElement.isClosure) {
       ClosureClassElement cls = member.enclosingElement;
-      if (cls.supertype.element == backend.helpers.boundClosureClass) {
+      if (cls.supertype.element == backend.commonElements.boundClosureClass) {
         reporter.internalError(cls.methodElement, 'Bound closure1.');
       }
       if (cls.methodElement.isInstanceMember) {
         reporter.internalError(cls.methodElement, 'Bound closure2.');
       }
     }
 
     // The set of selectors that apply to `member`. For example, for
     // a member `foo(x, [y])` the following selectors may apply:
     // `foo(x)`, and `foo(x, y)`.
@@ skipping 72 matching lines @@
             generateParameterStub(member, selector, null);
         if (stub != null) {
           stubs.add(stub);
         }
       }
     }
 
     return stubs;
   }
 }