Parse metadata, but ignore it.

dart/lib/compiler/implementation/scanner/partial_parser.dart

Index: dart/lib/compiler/implementation/scanner/partial_parser.dart
diff --git a/dart/lib/compiler/implementation/scanner/partial_parser.dart b/dart/lib/compiler/implementation/scanner/partial_parser.dart
index 38c3dd8646778a9fd87062cb67d561fe7522de28..9777c6ff0a7e3ef0c4484d3e5ef7996c0cc5eaf4 100644
--- a/dart/lib/compiler/implementation/scanner/partial_parser.dart
+++ b/dart/lib/compiler/implementation/scanner/partial_parser.dart
@@ -11,6 +11,17 @@ class PartialParser extends Parser {
 
   Token parseExpression(Token token) => skipExpression(token);
 
+  Token parseArgumentsOpt(Token token) {
+    // This method is overridden for two reasons:
+    // 1. Avoid generating events for arguments.
+    // 2. Avoid calling skip expression for each argument (which doesn't work).
+    if (optional('(', token)) {
+      return token.endGroup.next;
+    } else {
+      return token;
+    }
+  }
+
   Token skipExpression(Token token) {
     while (true) {
       final kind = token.kind;