Do not delete blink::WebRTCCertificateCallback on non-main thread

base/sequenced_task_runner_unittest.cc

+// Copyright 2016 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/sequenced_task_runner.h"
+
+#include "base/bind.h"
+#include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "base/threading/thread.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace {
+
+struct DeleteCounter {
+  DeleteCounter(int* counter, scoped_refptr<SequencedTaskRunner> task_runner)
+      : counter_(counter),
+        task_runner_(std::move(task_runner)) {
+  }
+  ~DeleteCounter() {
+    ++*counter_;
+    EXPECT_TRUE(!task_runner_ || task_runner_->RunsTasksOnCurrentThread());
+  }
+
+  int* counter_;
+  scoped_refptr<SequencedTaskRunner> task_runner_;
+};
+
+}  // namespace
+
+TEST(SequencedTaskRunnerTest, OnTaskRunnerDeleter) {
+  base::MessageLoop message_loop;
+  base::Thread thread("Foreign");
+  thread.Start();
+
+  scoped_refptr<SequencedTaskRunner> current_thread =
+      message_loop.task_runner();
+  scoped_refptr<SequencedTaskRunner> foreign_thread =
+      thread.task_runner();
+
+  using SequenceBoundUniquePtr =
+      std::unique_ptr<DeleteCounter, OnTaskRunnerDeleter>;
+
+  int counter = 0;
+  SequenceBoundUniquePtr ptr(new DeleteCounter(&counter, current_thread),
+                             OnTaskRunnerDeleter(current_thread));
+  EXPECT_EQ(0, counter);
+  foreign_thread->PostTask(
+      FROM_HERE,
+      Bind([](SequenceBoundUniquePtr) {},
+           Passed(&ptr)));
+
+  {
+    RunLoop run_loop;
+    foreign_thread->PostTaskAndReply(
+        FROM_HERE,
+        Bind([]{}),
+        run_loop.QuitClosure());
+    run_loop.Run();
+  }
+  EXPECT_EQ(1, counter);
+
+  DeleteCounter* raw = new DeleteCounter(&counter, nullptr);
+  SequenceBoundUniquePtr ptr2(raw, OnTaskRunnerDeleter(foreign_thread));
+  EXPECT_EQ(1, counter);
+
+  thread.Stop();
+  ptr2 = nullptr;
+  ASSERT_EQ(1, counter);
+
+  delete raw;
+  EXPECT_EQ(2, counter);
+}
+
+}  // namespace base