Use cammelCase for all service extension variables

runtime/observatory/tests/service/tcp_socket_closing_service_test.dart

 // Copyright (c) 2015, 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.
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io' as io;
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
@@ skipping 44 matching lines @@
   // Initial.
   (Isolate isolate) async {
     var result = await isolate.invokeRpcNoUpgrade('__getOpenSockets', {});
     expect(result['type'], equals('_opensockets'));
     // We expect only one socket to be open, the server socket create at the
     // end of test.
     expect(result['data'].length, equals(1));
     var server = await isolate.invokeRpcNoUpgrade(
         '__getSocketByID', { 'id' : result['data'][0]['id'] });
     expect(server['listening'], isTrue);
-    expect(server['last_read'], equals(0));
-    expect(server['total_read'], equals(0));
-    expect(server['last_write'], equals(0));
-    expect(server['total_written'], equals(0));
-    expect(server['write_count'], equals(0));
-    expect(server['read_count'], equals(0));
+    expect(server['lastRead'], equals(0));
+    expect(server['totalRead'], equals(0));
+    expect(server['lastWrite'], equals(0));
+    expect(server['totalWritten'], equals(0));
+    expect(server['writeCount'], equals(0));
+    expect(server['readCount'], equals(0));
   },
 ];
 
 main(args) async => runIsolateTests(args, tests, testeeBefore:setup);