Add a new node in the inferrer to materialize literal maps.

sdk/lib/_internal/compiler/implementation/inferrer/inferrer_visitor.dart

 // Copyright (c) 2013, 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 inferrer_visitor;
 
 import '../dart2jslib.dart' hide Selector, TypedSelector;
 import '../dart_types.dart';
 import '../elements/elements.dart';
 import '../tree/tree.dart';
@@ skipping 24 matching lines @@
   T get stringType;
   T get typeType;
 
   T nonNullSubtype(ClassElement type);
   T nonNullSubclass(ClassElement type);
   T nonNullExact(ClassElement type);
   T nonNullEmpty();
   bool isNull(T type);
   Selector newTypedSelector(T receiver, Selector selector);
 
-  T allocateContainer(T type,
-                      Node node,
-                      Element enclosing,
-                      [T elementType, int length]);
+  T allocateList(T type,
+                 Node node,
+                 Element enclosing,
+                 [T elementType, int length]);
+
+  T allocateMap(T keyType, T valueType, T type);
 
   /**
    * Returns the least upper bound between [firstType] and
    * [secondType].
    */
   T computeLUB(T firstType, T secondType);
 
   /**
    * Returns the intersection between [T] and [annotation].
    * [isNullable] indicates whether the annotation implies a null
@@ skipping 1090 matching lines @@
     return type;
   }
 
   T visitCascade(Cascade node) {
     // Ignore the result of the cascade send and return the type of the cascade
     // receiver.
     visit(node.expression);
     return cascadeReceiverStack.removeLast();
   }
 }