Lower map literals to constructor or function calls in builder

pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.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 tree_ir.optimization.statement_rewriter;
 
 import 'optimization.dart' show Pass;
 import '../tree_ir_nodes.dart';
 import '../../io/source_information.dart';
 import '../../elements/elements.dart';
@@ skipping 719 matching lines @@
 
   Expression visitThis(This node) {
     return node;
   }
 
   Expression visitLiteralList(LiteralList node) {
     _rewriteList(node.values);
     return node;
   }
 
-  Expression visitLiteralMap(LiteralMap node) {
-    // Process arguments right-to-left, the opposite of evaluation order.
-    for (LiteralMapEntry entry in node.entries.reversed) {
-      entry.value = visitExpression(entry.value);
-      entry.key = visitExpression(entry.key);
-    }
-    return node;
-  }
-
   Expression visitTypeOperator(TypeOperator node) {
     _rewriteList(node.typeArguments);
     node.value = visitExpression(node.value);
     return node;
   }
 
   bool sameVariable(Expression e1, Expression e2) {
     return e1 is VariableUse && e2 is VariableUse && e1.variable == e2.variable;
   }
 
@@ skipping 590 matching lines @@
   VariableUseCallback callback;
 
   VariableUseVisitor(this.callback);
 
   visitVariableUse(VariableUse use) => callback(use);
 
   static void visit(Expression node, VariableUseCallback callback) {
     new VariableUseVisitor(callback).visitExpression(node);
   }
 }