Remove HRuntimeType implementation

pkg/compiler/lib/src/js_backend/backend_impact.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_helpers.impact;
 
 import '../common/names.dart';
 import '../compiler.dart' show Compiler;
 import '../core_types.dart' show CommonElements;
 import '../elements/resolution_types.dart' show ResolutionInterfaceType;
@@ skipping 485 matching lines @@
 
   BackendImpact get typeVariableCheckedModeTypeCheck {
     return _typeVariableCheckedModeTypeCheck ??=
         new BackendImpact(staticUses: [helpers.assertSubtypeOfRuntimeType]);
   }
 
   BackendImpact _functionTypeCheck;
 
   BackendImpact get functionTypeCheck {
     return _functionTypeCheck ??=
-        new BackendImpact(staticUses: [helpers.functionTypeTestMetaHelper]);
+        new BackendImpact(staticUses: [/*helpers.functionTypeTestMetaHelper*/]);

[floitsch, 2017/03/02 13:43:38]

Please add a comment explaining why the dead code is not removed.

   }
 
   BackendImpact _nativeTypeCheck;
 
   BackendImpact get nativeTypeCheck {
     return _nativeTypeCheck ??= new BackendImpact(staticUses: [
       // We will neeed to add the "$is" and "$as" properties on the
       // JavaScript object prototype, so we make sure
       // [:defineProperty:] is compiled.
       helpers.defineProperty
@@ skipping 211 matching lines @@
 
   BackendImpact _staticClosure;
 
   /// Backend impact for performing closurization of a top-level or static
   /// function.
   BackendImpact get staticClosure {
     return _staticClosure ??=
         new BackendImpact(globalClasses: [helpers.closureClass]);
   }
 }