TaskScheduler [11] Support ExecutionMode::SINGLE_THREADED.

base/task_scheduler/scheduler_worker_thread_unittest.cc

Index: base/task_scheduler/scheduler_worker_thread_unittest.cc
diff --git a/base/task_scheduler/scheduler_worker_thread_unittest.cc b/base/task_scheduler/scheduler_worker_thread_unittest.cc
index 36fa42369fd5ef7d79be6c305860660dcb81d56d..2a9d5c69778c884143eff6ac6bd90d5e48a8fc2c 100644
--- a/base/task_scheduler/scheduler_worker_thread_unittest.cc
+++ b/base/task_scheduler/scheduler_worker_thread_unittest.cc
@@ -31,7 +31,8 @@ class TaskSchedulerWorkerThreadTest : public testing::TestWithParam<size_t> {
  protected:
   TaskSchedulerWorkerThreadTest()
       : main_entry_called_(true, false),
-        num_get_work_cv_(lock_.CreateConditionVariable()) {}
+        num_get_work_cv_(lock_.CreateConditionVariable()),
+        worker_thread_set_(true, false) {}
 
   void SetUp() override {
     worker_thread_ = SchedulerWorkerThread::Create(
@@ -39,6 +40,7 @@ class TaskSchedulerWorkerThreadTest : public testing::TestWithParam<size_t> {
         WrapUnique(new TestSchedulerWorkerThreadDelegate(this)),
         &task_tracker_);
     ASSERT_TRUE(worker_thread_);
+    worker_thread_set_.Signal();
     main_entry_called_.Wait();
   }
 
@@ -91,7 +93,10 @@ class TaskSchedulerWorkerThreadTest : public testing::TestWithParam<size_t> {
         : outer_(outer) {}
 
     // SchedulerWorkerThread::Delegate:
-    void OnMainEntry() override {
+    void OnMainEntry(SchedulerWorkerThread* worker_thread) override {
+      outer_->worker_thread_set_.Wait();
+      EXPECT_EQ(outer_->worker_thread_.get(), worker_thread);
+
       // Without synchronization, OnMainEntry() could be called twice without
       // generating an error.
       AutoSchedulerLock auto_lock(outer_->lock_);
@@ -200,6 +205,9 @@ class TaskSchedulerWorkerThreadTest : public testing::TestWithParam<size_t> {
   // Number of times that RunTaskCallback() has been called.
   size_t num_run_tasks_ = 0;
 
+  // Signaled after |worker_thread_| is set.
+  WaitableEvent worker_thread_set_;
+
   DISALLOW_COPY_AND_ASSIGN(TaskSchedulerWorkerThreadTest);
 };