Add begin events for const and new expressions.

pkg/front_end/lib/src/fasta/kernel/body_builder.dart

 // Copyright (c) 2016, 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 fasta.body_builder;
 
 import '../parser/parser.dart' show FormalParameterType, optional;
 
 import '../parser/error_kind.dart' show ErrorKind;
 
@@ skipping 1639 matching lines @@
       arguments.types.clear();
       for (int i = 0; i < typeParameters.length; i++) {
         arguments.types.add(const DynamicType());
       }
     }
 
     return true;
   }
 
   @override
-  void handleNewExpression(Token token) {
+  void endNewExpression(Token token) {
     debugEvent("NewExpression");
     Arguments arguments = pop();
     String name = pop();
     List<DartType> typeArguments = pop();
     var type = pop();
 
     if (arguments == null) {
       push(buildCompileTimeError("No arguments.", token.charOffset));
       return;
     }
@@ skipping 32 matching lines @@
         errorName = debugName(type.name, name);
       }
     } else {
       errorName = debugName(getNodeName(type), name);
     }
     errorName ??= name;
     push(throwNoSuchMethodError(errorName, arguments, token.charOffset));
   }
 
   @override
-  void handleConstExpression(Token token) {
-    debugEvent("ConstExpression");
-    handleNewExpression(token);
+  void endConstExpression(Token token) {
+    debugEvent("endConstExpression");
+    endNewExpression(token);
   }
 
   @override
   void endTypeArguments(int count, Token beginToken, Token endToken) {
     debugEvent("TypeArguments");
     push(popList(count));
   }
 
   @override
   void handleThisExpression(Token token, IdentifierContext context) {
@@ skipping 1013 matching lines @@
   } else if (node is PrefixBuilder) {
     return node.name;
   } else if (node is ThisAccessor) {
     return node.isSuper ? "super" : "this";
   } else if (node is BuilderAccessor) {
     return node.plainNameForRead;
   } else {
     return internalError("Unhandled: ${node.runtimeType}");
   }
 }