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..9eee5f374388ffcafd04cfa75383eb984bf4e91c 100644
--- a/base/task_scheduler/scheduler_worker_thread_unittest.cc
+++ b/base/task_scheduler/scheduler_worker_thread_unittest.cc
@@ -44,6 +44,11 @@ class TaskSchedulerWorkerThreadTest : public testing::TestWithParam<size_t> {
 
   void TearDown() override {
     worker_thread_->JoinForTesting();
+
+    {
+      AutoSchedulerLock auto_lock(main_entry_worker_thread_lock_);
+      EXPECT_EQ(worker_thread_.get(), main_entry_worker_thread_);
+    }
   }
 
   size_t TasksPerSequence() const { return GetParam(); }
@@ -91,7 +96,12 @@ class TaskSchedulerWorkerThreadTest : public testing::TestWithParam<size_t> {
         : outer_(outer) {}
 
     // SchedulerWorkerThread::Delegate:
-    void OnMainEntry() override {
+    void OnMainEntry(SchedulerWorkerThread* worker_thread) override {
+      {
+        AutoSchedulerLock auto_lock(outer_->main_entry_worker_thread_lock_);
+        outer_->main_entry_worker_thread_ = worker_thread;

[gab, 2016/04/26 11:46:27]

Why can't this directly compare to |worker_thread_| instead of waiting until
TearDown()? Is it because of thread-safety with SetUp()? Feels we could make
this work with some synchronization logic, feels weird to have this store state
merely to verify it in TearDown()..

[fdoray, 2016/04/26 14:56:47]

OnMainEntry() may be called before |worker_thread_| is set by SetUp(). I now use
an event to wait until |worker_thread_| is set.

+      }
+
       // Without synchronization, OnMainEntry() could be called twice without
       // generating an error.
       AutoSchedulerLock auto_lock(outer_->lock_);
@@ -200,6 +210,12 @@ class TaskSchedulerWorkerThreadTest : public testing::TestWithParam<size_t> {
   // Number of times that RunTaskCallback() has been called.
   size_t num_run_tasks_ = 0;
 
+  // Synchronizes access to |main_entry_worker_thread_|.
+  SchedulerLock main_entry_worker_thread_lock_;
+
+  // The worker thread argument passed to OnMainEntry().
+  SchedulerWorkerThread* main_entry_worker_thread_ = nullptr;
+
   DISALLOW_COPY_AND_ASSIGN(TaskSchedulerWorkerThreadTest);
 };