base: Let ThreadTaskRunnerHandle::Get() return NULL

base/thread_task_runner_handle_unittest.cc

Index: base/thread_task_runner_handle_unittest.cc
diff --git a/base/thread_task_runner_handle_unittest.cc b/base/thread_task_runner_handle_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..91671349907bda1468fcbc08dac12d9f65d3dc76
--- /dev/null
+++ b/base/thread_task_runner_handle_unittest.cc
@@ -0,0 +1,21 @@
+// 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/thread_task_runner_handle.h"
+
+#include "base/test/test_simple_task_runner.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+TEST(ThreadTaskRunnerHandleTest, NullRunner) {
+  EXPECT_FALSE(ThreadTaskRunnerHandle::IsSet());
+  EXPECT_EQ(nullptr, ThreadTaskRunnerHandle::Get());
+  scoped_refptr<TestSimpleTaskRunner> task_runner(new TestSimpleTaskRunner);
+  ThreadTaskRunnerHandle handle(task_runner);
+  EXPECT_TRUE(ThreadTaskRunnerHandle::IsSet());
+  EXPECT_EQ(task_runner, ThreadTaskRunnerHandle::Get());
+}
+
+}  // namespace base