Flatten inferrer implementation

pkg/compiler/lib/src/inferrer/map_tracer.dart

 // Copyright (c) 2014, 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 compiler.src.inferrer.map_tracer;
 
 import '../elements/elements.dart';
 import '../js_backend/backend_helpers.dart';
 import '../universe/selector.dart' show Selector;
 import 'node_tracer.dart';
@@ skipping 13 matching lines @@
   "keys",
   "length",
   "values",
   "clear",
   "containsKey",
   "containsValue",
   "forEach",
   "remove"
 ]);
 
-class MapTracerVisitor extends TracerVisitor<MapTypeInformation> {
+class MapTracerVisitor extends TracerVisitor {
   // These lists are used to keep track of newly discovered assignments to
   // the map. Note that elements at corresponding indices are expected to
   // belong to the same assignment operation.
   List<TypeInformation> keyAssignments = <TypeInformation>[];
   List<TypeInformation> valueAssignments = <TypeInformation>[];
   // This list is used to keep track of assignments of entire maps to
   // this map.
   List<MapTypeInformation> mapAssignments = <MapTypeInformation>[];
 
   MapTracerVisitor(tracedType, inferrer) : super(tracedType, inferrer);
@@ skipping 76 matching lines @@
           return;
         }
       }
     } else if (selector.isCall &&
         !info.targets.every((element) => element.isFunction)) {
       bailout('Passed to a closure');
       return;
     }
   }
 }