Speculative patch: Make it safe to delete the TQM inside a Task

content/child/scheduler/task_queue_manager_unittest.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 "content/child/scheduler/task_queue_manager.h"
 
 #include "base/threading/thread.h"
 #include "cc/test/ordered_simple_task_runner.h"
 #include "cc/test/test_now_source.h"
 #include "content/child/scheduler/nestable_task_runner_for_test.h"
@@ skipping 80 matching lines @@
   }
 
  private:
   std::deque<size_t> queues_to_service_;
   std::vector<const base::TaskQueue*> work_queues_;
 
   DISALLOW_COPY_AND_ASSIGN(ExplicitSelectorForTest);
 };
 
 class TaskQueueManagerTest : public testing::Test {
+ public:
+  void DeleteTaskQueueManager() {
+    manager_.reset();
+  }
+
  protected:
   enum class SelectorType {
     Automatic,
     Explicit,
   };
 
   void Initialize(size_t num_queues, SelectorType type) {
     now_src_ = cc::TestNowSource::Create(1000);
     test_task_runner_ =
         make_scoped_refptr(new cc::OrderedSimpleTaskRunner(now_src_, false));
@@ skipping 918 matching lines @@
   base::TimeDelta delay2 = base::TimeDelta::FromMilliseconds(5);
   base::TimeDelta delay3 = base::TimeDelta::FromMilliseconds(10);
   runners[0]->PostDelayedTask(FROM_HERE, base::Bind(&NopTask), delay1);
   runners[1]->PostDelayedTask(FROM_HERE, base::Bind(&NopTask), delay2);
   runners[2]->PostDelayedTask(FROM_HERE, base::Bind(&NopTask), delay3);
 
   EXPECT_EQ(now_src_->Now() + delay2,
             manager_->NextPendingDelayedTaskRunTime());
 }
 
+TEST_F(TaskQueueManagerTest, DeleteTqmInTask) {

[Sami, 2015/04/08 14:24:04]

nit: s/Tqm/Manager/ or something since we're not really using that abbreviation
outside comments.

[alex clarke (OOO till 29th), 2015/04/08 14:33:05]

Done.

+  Initialize(1u, SelectorType::Automatic);
+
+  scoped_refptr<base::SingleThreadTaskRunner> runner =
+      manager_->TaskRunnerForQueue(0);
+  runner->PostTask(FROM_HERE,
+                   base::Bind(&TaskQueueManagerTest::DeleteTaskQueueManager,
+                              base::Unretained(this)));
+
+  // This should not crash, assuming DoWork detects the TaskQueueManager has
+  // been deleted.
+  test_task_runner_->RunUntilIdle();
+}
+
 }  // namespace
 }  // namespace content