Fix for issue 28196 - constant interceptors for mixin applications

pkg/compiler/lib/src/js_backend/namer.dart

 // Copyright (c) 2011, 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 js_backend.namer;
 
 import 'dart:collection' show HashMap;
 
 import 'package:js_runtime/shared/embedded_names.dart' show JsGetName;
 
@@ skipping 1874 matching lines @@
     if (name == null) {
       // e.g. DartType 'dynamic' has no element.
       name = rtiEncoder.getTypeRepresentationForTypeConstant(type);
     }
     addIdentifier(name);
     add(getHashTag(constant, 3));
   }
 
   @override
   void visitInterceptor(InterceptorConstantValue constant, [_]) {
-    addRoot(constant.cls.name);
+    // The class name for mixin applications contain '+' signs (issue 28196).
+    addRoot(constant.cls.name.replaceAll('+', '_'));
     add('methods');
   }
 
   @override
   void visitSynthetic(SyntheticConstantValue constant, [_]) {
     switch (constant.valueKind) {
       case SyntheticConstantKind.DUMMY_INTERCEPTOR:
         add('dummy_receiver');
         break;
       case SyntheticConstantKind.TYPEVARIABLE_REFERENCE:
@@ skipping 277 matching lines @@
   void addSuggestion(String original, String suggestion) {
     assert(!_suggestedNames.containsKey(original));
     _suggestedNames[original] = suggestion;
   }
 
   bool hasSuggestion(String original) => _suggestedNames.containsKey(original);
   bool isSuggestion(String candidate) {
     return _suggestedNames.containsValue(candidate);
   }
 }