Repeated prefixes and parser fixes.

dart/frog/leg/scanner/partial_parser.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class PartialParser extends Parser {
   PartialParser(Listener listener) : super(listener);
 
   Token parseClassBody(Token token) => skipClassBody(token);
 
   Token fullParseClassBody(Token token) => super.parseClassBody(token);
 
   Token parseExpression(Token token) => skipExpression(token);
 
   Token skipExpression(Token token) {
     while (true) {
       final kind = token.kind;
       final value = token.stringValue;
       if ((kind === EOF_TOKEN) ||
           (value === ';') ||
           (value === ',') ||
           (value === ']'))
         return token;
+      if (value === '=' && token.next.stringValue === '{') {
+        // Handle cases like this:
+        // class Foo {
+        //   var map;
+        //   Foo() : map = {};
+        // }
+        BeginGroupToken begin = token.next;
+        token = (begin.endGroup !== null) ? begin.endGroup : token;
+        token = token.next;
+        continue;
+      }
       if (!mayParseFunctionExpressions && value === '{')
         return token;
       if ((value !== '<') && (token is BeginGroupToken)) {
         BeginGroupToken begin = token;
         token = (begin.endGroup !== null) ? begin.endGroup : token;
       }
       token = token.next;
     }
   }
 
@@ skipping 34 matching lines @@
         return token;
       }
       return listener.unexpected(token);
     }
     BeginGroupToken beginGroupToken = token;
     Token endToken = beginGroupToken.endGroup;
     listener.endFormalParameters(0, token, endToken);
     return endToken.next;
   }
 }