Protobuf changes for smaller dart2js code, Int64 fixes

test/generated_message_test.dart

 #!/usr/bin/env dart
 // Copyright (c) 2013, 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.
 
 library generated_message_test;
 
 import 'package:protobuf/protobuf.dart';
 import 'package:unittest/unittest.dart';
 
@@ skipping 129 matching lines @@
         new TestExtremeDefaultValues();
 
     expect(message.utf8String, '\u1234');
     expect(message.infDouble, same(double.INFINITY));
     expect(message.negInfDouble, same(double.NEGATIVE_INFINITY));
     expect(message.nanDouble, same(double.NAN));
     expect(message.infFloat, same(double.INFINITY));
     expect(message.negInfFloat, same(double.NEGATIVE_INFINITY));
     expect(message.nanFloat, same(double.NAN));
     expect(message.cppTrigraph, '? ? ?? ?? ??? ??/ ??-');
+    expect(message.smallInt64.toRadixString(16).toUpperCase(),
+        '-7FFFFFFFFFFFFFFF');
   });
 
   test('testClear', () {
     TestAllTypes message = new TestAllTypes();
 
     assertClear(message);
     setAllFields(message);
     message.clear();
     assertClear(message);
   });
@@ skipping 551 matching lines @@
     message.m2M = new p2.M_M();
     message.m3 = new p3.M();
     message.m3M = new p3.M_M();
   });
 
   test('testToplevel', () {
     t.M message = new t.M();
     message.t = new T();
   });
 }