Clean up FunctionDefinition in the IR S-expression representation.

tests/compiler/dart2js/backend_dart/sexpr_unstringifier.dart

 // Copyright (c) 2014, 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.
 
 // SExpressionUnstringifier implements the inverse operation to
 // [SExpressionStringifier].
 
 library sexpr_unstringifier;
 
 import 'package:compiler/src/constants/expressions.dart'
@@ skipping 253 matching lines @@
     tokens.consumeEnd();
     return prims;
   }
 
   /// (FunctionDefinition name (args cont) body)
   FunctionDefinition parseFunctionDefinition() {
     tokens.consumeStart(FUNCTION_DEFINITION);
 
     // name
     Element element = new DummyElement("");
-    if (tokens.current != '(' && tokens.current != '{') {
+    if (tokens.current != '(') {
       // This is a named function.
       element = new DummyElement(tokens.read());
     }
 
-    // [closure-vars]
-    List<ClosureVariable> closureVariables = <ClosureVariable>[];
-    if (tokens.current == '{') {
-      tokens.read('{');
-      while (tokens.current != '}') {
-        String varName = tokens.read();
-        ClosureVariable variable =
-            new ClosureVariable(element, new DummyElement(varName));
-        closureVariables.add(variable);
-        name2variable[varName] = variable;
-      }
-      tokens.read('}');
-    }
-
-    // (args cont)
+    // (parameters)
     List<Definition> parameters = <Definition>[];
     tokens.consumeStart();
-    while (tokens.next != ")") {
+    while (tokens.current != ")") {
       String paramName = tokens.read();
       if (name2variable.containsKey(paramName)) {
         parameters.add(name2variable[paramName]);
       } else {
         Parameter param = new Parameter(new DummyElement(paramName));
         name2variable[paramName] = param;
         parameters.add(param);
       }
     }
+    tokens.consumeEnd();
 
+    // continuation
     String contName = tokens.read("return");
     Continuation cont = name2variable[contName];
     assert(cont != null);
+
+    // [closure-variables]
+    List<ClosureVariable> closureVariables = <ClosureVariable>[];
+    tokens.consumeStart();
+    while (tokens.current != ')') {
+      String varName = tokens.read();
+      ClosureVariable variable =
+          new ClosureVariable(element, new DummyElement(varName));
+      closureVariables.add(variable);
+      name2variable[varName] = variable;
+    }
     tokens.consumeEnd();
 
     // body
     Expression body = parseExpression();
 
     tokens.consumeEnd();
     return new FunctionDefinition(element, cont, parameters, body, null, null,
         closureVariables);
   }
 
@@ skipping 383 matching lines @@
     return new ReifyTypeVar(type);
   }
 
   /// (This)
   This parseThis() {
     tokens.consumeStart(THIS);
     tokens.consumeEnd();
     return new This();
   }
 }