Add ability to look up type parameters that are associated with ClassEntities with the element envi…

pkg/compiler/lib/src/resolution/resolution_strategy.dart

 // Copyright (c) 2017, 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.resolution_strategy;
 
 import 'package:front_end/src/fasta/scanner.dart' show Token;
 
 import '../../compiler_new.dart' as api;
 import '../common.dart';
@@ skipping 666 matching lines @@
     return type;
   }
 
   @override
   DartType getFieldType(covariant FieldElement field) {
     field.computeType(_resolution);
     return field.type;
   }
 
   @override
+  List<DartType> getTypeVariables(covariant ClassElement cls) {
+    return cls.typeVariables;
+  }
+
+  @override
   ResolutionFunctionType getLocalFunctionType(
       covariant LocalFunctionElement function) {
     return function.type;
   }
 
   @override
   ConstantExpression getFieldConstant(covariant FieldElement field) {
     return field.constant;
   }
 
@@ skipping 276 matching lines @@
 
   @override
   void forEachConstructor(
       covariant ClassElement cls, void f(ConstructorEntity constructor)) {
     cls.constructors.forEach((Element _constructor) {
       ConstructorElement constructor = _constructor;
       f(constructor);
     });
   }
 }