Parse metadata, but ignore it.

dart/lib/compiler/implementation/scanner/token.dart

Index: dart/lib/compiler/implementation/scanner/token.dart
diff --git a/dart/lib/compiler/implementation/scanner/token.dart b/dart/lib/compiler/implementation/scanner/token.dart
index dab6d60ba3a3b93d414cc177e34e544eb6d1af80..2fb0d6df0d26e3ffb0d273928b4da561d12482b2 100644
--- a/dart/lib/compiler/implementation/scanner/token.dart
+++ b/dart/lib/compiler/implementation/scanner/token.dart
@@ -29,6 +29,7 @@ final int MINUS_TOKEN = $MINUS;
 final int PERIOD_TOKEN = $PERIOD;
 final int PLUS_TOKEN = $PLUS;
 final int QUESTION_TOKEN = $QUESTION;
+final int AT_TOKEN = $AT;
 final int CLOSE_CURLY_BRACKET_TOKEN = $CLOSE_CURLY_BRACKET;
 final int CLOSE_SQUARE_BRACKET_TOKEN = $CLOSE_SQUARE_BRACKET;
 final int CLOSE_PAREN_TOKEN = $CLOSE_PAREN;
@@ -330,6 +331,9 @@ final PrecedenceInfo SEMICOLON_INFO =
 final PrecedenceInfo COMMA_INFO =
   const PrecedenceInfo(const SourceString(','), 0, COMMA_TOKEN);
 
+final PrecedenceInfo AT_INFO =
+  const PrecedenceInfo(const SourceString('@'), 0, AT_TOKEN);
+
 // Assignment operators.
 final int ASSIGNMENT_PRECEDENCE = 1;
 final PrecedenceInfo AMPERSAND_EQ_INFO =