Relax check for message loop in SequencedWorkerPool

base/threading/sequenced_worker_pool.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 "base/threading/sequenced_worker_pool.h"
 
 #include <list>
 #include <map>
 #include <set>
 #include <utility>
@@ skipping 674 matching lines @@
 }
 
 // SequencedWorkerPool --------------------------------------------------------
 
 SequencedWorkerPool::SequencedWorkerPool(
     size_t max_threads,
     const std::string& thread_name_prefix)
     : constructor_message_loop_(MessageLoopProxy::current()),
       inner_(new Inner(ALLOW_THIS_IN_INITIALIZER_LIST(this),
                        max_threads, thread_name_prefix, NULL)) {
-  DCHECK(constructor_message_loop_.get());
 }
 
 SequencedWorkerPool::SequencedWorkerPool(
     size_t max_threads,
     const std::string& thread_name_prefix,
     TestingObserver* observer)
     : constructor_message_loop_(MessageLoopProxy::current()),
       inner_(new Inner(ALLOW_THIS_IN_INITIALIZER_LIST(this),
                        max_threads, thread_name_prefix, observer)) {
-  DCHECK(constructor_message_loop_.get());
 }
 
 SequencedWorkerPool::~SequencedWorkerPool() {}
 
 void SequencedWorkerPool::OnDestruct() const {
-  // TODO(akalin): Once we can easily check if we're on a worker
-  // thread or not, use that instead of restricting destruction to
-  // only the constructor message loop.
-  if (constructor_message_loop_->BelongsToCurrentThread())
+  DCHECK(constructor_message_loop_.get());
+  // Avoid deleting ourselves on a worker thread (which would
+  // deadlock).
+  if (RunsTasksOnCurrentThread()) {
+    constructor_message_loop_->DeleteSoon(FROM_HERE, this);
+  } else {
     delete this;
-  else
-    constructor_message_loop_->DeleteSoon(FROM_HERE, this);
+  }
 }
 
 SequencedWorkerPool::SequenceToken SequencedWorkerPool::GetSequenceToken() {
   return inner_->GetSequenceToken();
 }
 
 SequencedWorkerPool::SequenceToken SequencedWorkerPool::GetNamedSequenceToken(
     const std::string& name) {
   return inner_->GetNamedSequenceToken(name);
 }
@@ skipping 68 matching lines @@
 void SequencedWorkerPool::SignalHasWorkForTesting() {
   inner_->SignalHasWorkForTesting();
 }
 
 void SequencedWorkerPool::Shutdown() {
   DCHECK(constructor_message_loop_->BelongsToCurrentThread());
   inner_->Shutdown();
 }
 
 }  // namespace base