Update the protocol buffer compiler plugin to use Int64 from the fixnum package

test/json_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 json_test;
 
 import 'package:protobuf/protobuf.dart';
 import 'package:unittest/unittest.dart';
 
 import '../out/protos/google/protobuf/unittest.pb.dart';
 
 import 'test_util.dart';
 
 void main() {
-  final String TEST_ALL_TYPES_JSON = '{"1":101,"2":"102","3":103,"4":"104",'
-      '"5":105,"6":"106","7":107,"8":"108","9":109,"10":"110","11":111.0,'
+  final String TEST_ALL_TYPES_JSON = '{"1":101,"2":102,"3":103,"4":104,'
+      '"5":105,"6":106,"7":107,"8":108,"9":109,"10":110,"11":111.0,'
       '"12":112.0,"13":true,"14":"115","15":"MTE2","16":{"17":117},'
       '"18":{"1":118},"19":{"1":119},"20":{"1":120},"21":3,"22":6,"23":9,'
-      '"24":"124","25":"125","31":[201,301],"32":["202","302"],'
-      '"33":[203,303],"34":["204","304"],"35":[205,305],"36":["206","306"],'
-      '"37":[207,307],"38":["208","308"],"39":[209,309],"40":["210","310"],'
+      '"24":"124","25":"125","31":[201,301],"32":[202,302],'
+      '"33":[203,303],"34":[204,304],"35":[205,305],"36":[206,306],'
+      '"37":[207,307],"38":[208,308],"39":[209,309],"40":[210,310],'
       '"41":[211.0,311.0],"42":[212.0,312.0],"43":[true,false],'
       '"44":["215","315"],"45":["MjE2","MzE2"],"46":[{"47":217},{"47":317}],'
       '"48":[{"1":218},{"1":318}],"49":[{"1":219},{"1":319}],'
       '"50":[{"1":220},{"1":320}],"51":[2,3],"52":[5,6],"53":[8,9],'
-      '"54":["224","324"],"55":["225","325"],"61":401,"62":"402","63":403,'
-      '"64":"404","65":405,"66":"406","67":407,"68":"408","69":409,'
-      '"70":"410","71":411.0,"72":412.0,"73":false,"74":"415","75":"NDE2",'
+      '"54":["224","324"],"55":["225","325"],"61":401,"62":402,"63":403,'
+      '"64":404,"65":405,"66":406,"67":407,"68":408,"69":409,'
+      '"70":410,"71":411.0,"72":412.0,"73":false,"74":"415","75":"NDE2",'
       '"81":1,"82":4,"83":7,"84":"424","85":"425"}';
 
   /**
    * Checks that message once serialized to JSON
    * matches TEST_ALL_TYPES_JSON massaged with [:.replaceAll(from, to):].
    */
   expectedJson(from, to) {
     var expectedJson = TEST_ALL_TYPES_JSON.replaceAll(from, to);
     return predicate(
         (message) => message.writeToJson() == expectedJson, 'Incorrect output');
   }
 
   test('testOutput', () {
     expect(getAllSet().writeToJson(), TEST_ALL_TYPES_JSON);
 
     // Test empty list.
     expect(getAllSet()..repeatedBool.clear(),
            expectedJson('"43":[true,false],', ''));
 
     // Test negative number.
     expect(getAllSet()..optionalInt32 = -1234567,
            expectedJson(':101,', ':-1234567,'));
 
-    // 64-bit numbers are quoted.
+    // 64-bit numbers outside 53-bit range are quoted.
     expect(getAllSet()..optionalInt64 = make64(0, 0x200000),
-           expectedJson(':"102",', ':"9007199254740992",'));
+           expectedJson(':102,', ':9007199254740992,'));
+    expect(getAllSet()..optionalInt64 = make64(1, 0x200000),
+           expectedJson(':102,', ':"9007199254740993",'));
+    expect(getAllSet()..optionalInt64 = -make64(0, 0x200000),
+           expectedJson(':102,', ':-9007199254740992,'));
+    expect(getAllSet()..optionalInt64 = -make64(1, 0x200000),
+           expectedJson(':102,', ':"-9007199254740993",'));
 
     // Quotes, backslashes, and control characters in strings are quoted.
     expect(getAllSet()..optionalString = 'a\u0000b\u0001cd\\e\"fg',
            expectedJson(':"115",', ':"a\\u0000b\\u0001cd\\\\e\\"fg",'));
   });
 
   test('testBase64Encode', () {
     expect(getAllSet()..optionalBytes = 'Hello, world'.codeUnits,
            expectedJson(':"MTE2",', ':"SGVsbG8sIHdvcmxk",'));
 
@@ skipping 43 matching lines @@
   test('testExtensionsOutput', () {
     expect(getAllExtensionsSet().writeToJson(), TEST_ALL_TYPES_JSON);
   });
 
   test('testExtensionsParse', () {
     ExtensionRegistry registry = getExtensionRegistry();
     expect(new TestAllExtensions.fromJson(TEST_ALL_TYPES_JSON, registry),
            getAllExtensionsSet());
   });
 }