Parse ParenthesizedExpression as Fasta.

pkg/front_end/lib/src/fasta/analyzer/ast_builder.dart

Index: pkg/front_end/lib/src/fasta/analyzer/ast_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/analyzer/ast_builder.dart b/pkg/front_end/lib/src/fasta/analyzer/ast_builder.dart
index 02a3eb24c4df5a23c16de9a0f218a987f8a9e883..ac90eec128258091ad62f7ead5133d28b7b59584 100644
--- a/pkg/front_end/lib/src/fasta/analyzer/ast_builder.dart
+++ b/pkg/front_end/lib/src/fasta/analyzer/ast_builder.dart
@@ -68,6 +68,14 @@ class AstBuilder extends ScopeListener {
     push(token);
   }
 
+  @override
+  void handleParenthesizedExpression(BeginGroupToken token) {
+    debugEvent("ParenthesizedExpression");
+    Expression expression = pop();
+    push(ast.parenthesizedExpression(
+        toAnalyzerToken(token), expression, toAnalyzerToken(token.endGroup)));
+  }
+
   void handleStringPart(Token token) {
     debugEvent("StringPart");
     push(token);