Support parameter metadata.

sdk/lib/_internal/compiler/implementation/scanner/parser.dart

Index: sdk/lib/_internal/compiler/implementation/scanner/parser.dart
diff --git a/sdk/lib/_internal/compiler/implementation/scanner/parser.dart b/sdk/lib/_internal/compiler/implementation/scanner/parser.dart
index 53f04db4ce008d075d40ebab800ee354b95aa083..365a92b77dd494807acab433eef5a8dfd26aa63f 100644
--- a/sdk/lib/_internal/compiler/implementation/scanner/parser.dart
+++ b/sdk/lib/_internal/compiler/implementation/scanner/parser.dart
@@ -215,10 +215,14 @@ class Parser {
     return token;
   }
 
-  Token parseMetadataStar(Token token) {
+  Token parseMetadataStar(Token token, {bool forParameter: false}) {
+    listener.beginMetadataStar(token);
+    int count = 0;
     while (optional('@', token)) {
       token = parseMetadata(token);
+      count++;
     }
+    listener.endMetadataStar(count, forParameter);
     return token;
   }
 
@@ -326,6 +330,7 @@ class Parser {
   }
 
   Token parseFormalParameter(Token token, FormalParameterType type) {
+    token = parseMetadataStar(token, forParameter: true);
     listener.beginFormalParameter(token);
     token = parseModifiers(token);
     // TODO(ahe): Validate that there are formal parameters if void.