Explain the reason why we don't have thread check in destructor of ByteStreamReader/WriterImpl

content/browser/byte_stream.cc

 // Copyright (c) 2012 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 "content/browser/byte_stream.h"
 
 #include <deque>
 #include <set>
 #include <utility>
 
@@ skipping 176 matching lines @@
       my_task_runner_(task_runner),
       my_lifetime_flag_(lifetime_flag),
       input_contents_size_(0),
       output_size_used_(0),
       peer_(NULL) {
   DCHECK(my_lifetime_flag_.get());
   my_lifetime_flag_->is_alive = true;
 }
 
 ByteStreamWriterImpl::~ByteStreamWriterImpl() {
+  // No RunsTasksOnCurrentThread() check to allow deleting a created writer
+  // before we start using it. Once started, should be deleted on the specified
+  // task runner.
   my_lifetime_flag_->is_alive = false;
 }
 
 void ByteStreamWriterImpl::SetPeer(
     ByteStreamReaderImpl* peer,
     scoped_refptr<base::SequencedTaskRunner> peer_task_runner,
     scoped_refptr<LifetimeFlag> peer_lifetime_flag) {
   peer_ = peer;
   peer_task_runner_ = peer_task_runner;
   peer_lifetime_flag_ = peer_lifetime_flag;
@@ skipping 109 matching lines @@
       my_lifetime_flag_(lifetime_flag),
       received_status_(false),
       status_(0),
       unreported_consumed_bytes_(0),
       peer_(NULL) {
   DCHECK(my_lifetime_flag_.get());
   my_lifetime_flag_->is_alive = true;
 }
 
 ByteStreamReaderImpl::~ByteStreamReaderImpl() {
+  // No RunsTasksOnCurrentThread() check to allow deleting a created writer
+  // before we start using it. Once started, should be deleted on the specified
+  // task runner.
   my_lifetime_flag_->is_alive = false;
 }
 
 void ByteStreamReaderImpl::SetPeer(
     ByteStreamWriterImpl* peer,
     scoped_refptr<base::SequencedTaskRunner> peer_task_runner,
     scoped_refptr<LifetimeFlag> peer_lifetime_flag) {
   peer_ = peer;
   peer_task_runner_ = peer_task_runner;
   peer_lifetime_flag_ = peer_lifetime_flag;
@@ skipping 117 matching lines @@
   ByteStreamReaderImpl* out = new ByteStreamReaderImpl(
       output_task_runner, output_flag, buffer_size);
 
   in->SetPeer(out, output_task_runner, output_flag);
   out->SetPeer(in, input_task_runner, input_flag);
   input->reset(in);
   output->reset(out);
 }
 
 }  // namespace content