Add SequencedTaskRunnerHandle to get a SequencedTaskRunner for the current thread / sequence.

base/threading/sequenced_task_runner_handle_unittest.cc

Index: base/threading/sequenced_task_runner_handle_unittest.cc
diff --git a/base/threading/sequenced_task_runner_handle_unittest.cc b/base/threading/sequenced_task_runner_handle_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..df7a1175c8090aa10ef865d681a75579eb4a1925
--- /dev/null
+++ b/base/threading/sequenced_task_runner_handle_unittest.cc
@@ -0,0 +1,81 @@
+// Copyright 2015 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/bind.h"
+#include "base/callback.h"
+#include "base/location.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "base/sequence_checker_impl.h"
+#include "base/sequenced_task_runner.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/threading/sequenced_task_runner_handle.h"
+#include "base/threading/sequenced_worker_pool.h"
+#include "base/threading/simple_thread.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace {
+
+class SequencedTaskRunnerHandleTest : public ::testing::Test {
+ protected:
+  static void GetTaskRunner(const Closure& callback) {
+    // Use SequenceCheckerImpl to make sure it's not a no-op in Release builds.
+    scoped_ptr<SequenceCheckerImpl> sequence_checker(new SequenceCheckerImpl);
+    ASSERT_TRUE(SequencedTaskRunnerHandle::IsSet());
+    scoped_refptr<SequencedTaskRunner> task_runner =
+        SequencedTaskRunnerHandle::Get();
+    ASSERT_TRUE(task_runner);
+    task_runner->PostTask(
+        FROM_HERE, base::Bind(&SequencedTaskRunnerHandleTest::CheckValidThread,
+                              base::Passed(&sequence_checker), callback));
+  }
+
+ private:
+  static void CheckValidThread(scoped_ptr<SequenceCheckerImpl> sequence_checker,
+                               const Closure& callback) {
+    EXPECT_TRUE(sequence_checker->CalledOnValidSequencedThread());
+    callback.Run();
+  }
+
+  MessageLoop message_loop_;
+};
+
+TEST_F(SequencedTaskRunnerHandleTest, FromMessageLoop) {
+  RunLoop run_loop;
+  GetTaskRunner(run_loop.QuitClosure());
+  run_loop.Run();
+}
+
+TEST_F(SequencedTaskRunnerHandleTest, FromSequencedWorkerPool) {
+  scoped_refptr<SequencedWorkerPool> pool(new SequencedWorkerPool(3, "Test"));
+  WaitableEvent event(false, false);
+  pool->PostSequencedWorkerTask(
+      pool->GetSequenceToken(), FROM_HERE,
+      base::Bind(&SequencedTaskRunnerHandleTest::GetTaskRunner,
+                 base::Bind(&WaitableEvent::Signal, base::Unretained(&event))));
+  event.Wait();
+}
+
+class ThreadRunner : public DelegateSimpleThread::Delegate {
+ public:
+  void Run() override {
+    ASSERT_FALSE(SequencedTaskRunnerHandle::IsSet());
+  }
+
+ private:
+  Closure callback_;
+};
+
+TEST_F(SequencedTaskRunnerHandleTest, FromSimpleThread) {
+  ThreadRunner thread_runner;
+  DelegateSimpleThread thread(&thread_runner, "Background thread");
+  thread.Start();
+  thread.Join();
+}
+
+}  // namespace
+}  // namespace base