[cast_channel] Make CastSocketService a global leaky singleton

components/cast_channel/cast_test_util.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/cast_channel/cast_test_util.h"
 
 #include <utility>
 
 #include "net/base/ip_address.h"
 
@@ skipping 11 matching lines @@
     std::unique_ptr<CastTransport::Delegate> delegate) {
   delegate_ = std::move(delegate);
 }
 
 MockCastTransportDelegate::MockCastTransportDelegate() {}
 MockCastTransportDelegate::~MockCastTransportDelegate() {}
 
 MockCastSocketObserver::MockCastSocketObserver() {}
 MockCastSocketObserver::~MockCastSocketObserver() {}
 
+MockCastSocketService::MockCastSocketService() {}
+MockCastSocketService::~MockCastSocketService() {}
+
 MockCastSocket::MockCastSocket()
     : channel_id_(0),
       error_state_(ChannelError::NONE),
       keep_alive_(false),
       audio_only_(false),
       mock_transport_(new MockCastTransport()) {}
 MockCastSocket::~MockCastSocket() {}
 
 net::IPEndPoint CreateIPEndPointForTest() {
   return net::IPEndPoint(net::IPAddress(192, 168, 1, 1), 8009);
 }
 
 }  // namespace cast_channel