Make TestSimpleTaskRunner thread-safe.

device/bluetooth/bluetooth_task_manager_win_unittest.cc

Index: device/bluetooth/bluetooth_task_manager_win_unittest.cc
diff --git a/device/bluetooth/bluetooth_task_manager_win_unittest.cc b/device/bluetooth/bluetooth_task_manager_win_unittest.cc
index 5071dffb7b972ecb15606157ac6c1c47f0346631..9ffd07ec6935565c74017145e2c20d8e62fd6086 100644
--- a/device/bluetooth/bluetooth_task_manager_win_unittest.cc
+++ b/device/bluetooth/bluetooth_task_manager_win_unittest.cc
@@ -82,14 +82,14 @@ class BluetoothTaskManagerWinTest : public testing::Test {
 };
 
 TEST_F(BluetoothTaskManagerWinTest, StartPolling) {
-  EXPECT_EQ(1u, bluetooth_task_runner_->GetPendingTasks().size());
+  EXPECT_EQ(1u, bluetooth_task_runner_->NumPendingTasks());
 }
 
 TEST_F(BluetoothTaskManagerWinTest, PollAdapterIfBluetoothStackIsAvailable) {
   bluetooth_task_runner_->RunPendingTasks();
   size_t num_expected_pending_tasks = has_bluetooth_stack_ ? 1 : 0;
   EXPECT_EQ(num_expected_pending_tasks,
-            bluetooth_task_runner_->GetPendingTasks().size());
+            bluetooth_task_runner_->NumPendingTasks());
 }
 
 TEST_F(BluetoothTaskManagerWinTest, Polling) {
@@ -114,9 +114,9 @@ TEST_F(BluetoothTaskManagerWinTest, SetPowered) {
   base::Closure closure;
   task_manager_->PostSetPoweredBluetoothTask(true, closure, closure);
 
-  EXPECT_EQ(1u, bluetooth_task_runner_->GetPendingTasks().size());
+  EXPECT_EQ(1u, bluetooth_task_runner_->NumPendingTasks());
   bluetooth_task_runner_->RunPendingTasks();
-  EXPECT_TRUE(ui_task_runner_->GetPendingTasks().size() >= 1);
+  EXPECT_TRUE(ui_task_runner_->NumPendingTasks() >= 1);
 }
 
 TEST_F(BluetoothTaskManagerWinTest, Discovery) {