Add begin events for const and new expressions.

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

Index: pkg/front_end/lib/src/fasta/kernel/body_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
index eb3293679c144ca580d42acaba414182fd435cf2..8097c4baf12a2cd514e3f577b63d069b735bff23 100644
--- a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
@@ -1657,7 +1657,7 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
   }
 
   @override
-  void handleNewExpression(Token token) {
+  void endNewExpression(Token token) {
     debugEvent("NewExpression");
     Arguments arguments = pop();
     String name = pop();
@@ -1710,9 +1710,9 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
   }
 
   @override
-  void handleConstExpression(Token token) {
-    debugEvent("ConstExpression");
-    handleNewExpression(token);
+  void endConstExpression(Token token) {
+    debugEvent("endConstExpression");
+    endNewExpression(token);
   }
 
   @override