Mojo: Make device/ to not rely on connecton error notification on message loop destruction.

device/serial/data_source_sender.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 "device/serial/data_source_sender.h"
 
 #include <algorithm>
 #include <limits>
 #include <memory>
 #include <utility>
@@ skipping 82 matching lines @@
       base::Bind(&DataSourceSender::OnConnectionError, base::Unretained(this)));
 }
 
 void DataSourceSender::ShutDown() {
   shut_down_ = true;
   ready_callback_.Reset();
   error_callback_.Reset();
 }
 
 DataSourceSender::~DataSourceSender() {
-  DCHECK(shut_down_);
 }
 
 void DataSourceSender::Init(uint32_t buffer_size) {
   available_buffer_capacity_ = buffer_size;
   GetMoreData();
 }
 
 void DataSourceSender::Resume() {
   if (pending_send_) {
     DispatchFatalError();
@@ skipping 130 matching lines @@
     uint32_t bytes_written,
     int32_t error) {
   DCHECK(sender_.get());
   PendingSend* send = pending_send_;
   pending_send_ = nullptr;
   send->DoneWithError(bytes_written, error);
   sender_ = nullptr;
 }
 
 }  // namespace device