Rename CancellationFlag to AtomicFlag.

base/task_scheduler/task_tracker_unittest.cc

Index: base/task_scheduler/task_tracker_unittest.cc
diff --git a/base/task_scheduler/task_tracker_unittest.cc b/base/task_scheduler/task_tracker_unittest.cc
index 58f47b8153458816889e15c31961b0e5aa9732cd..89f66bec7ae3b827aa0a66e3924b647e80df458f 100644
--- a/base/task_scheduler/task_tracker_unittest.cc
+++ b/base/task_scheduler/task_tracker_unittest.cc
@@ -16,6 +16,7 @@
 #include "base/memory/ref_counted.h"
 #include "base/sequenced_task_runner.h"
 #include "base/single_thread_task_runner.h"
+#include "base/synchronization/atomic_flag.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/task_scheduler/scheduler_lock.h"
 #include "base/task_scheduler/task.h"
@@ -40,22 +41,19 @@ constexpr size_t kLoadTestNumIterations = 100;
 class ThreadCallingShutdown : public SimpleThread {
  public:
   explicit ThreadCallingShutdown(TaskTracker* tracker)
-      : SimpleThread("ThreadCallingShutdown"),
-        tracker_(tracker),
-        has_returned_(WaitableEvent::ResetPolicy::MANUAL,
-                      WaitableEvent::InitialState::NOT_SIGNALED) {}
+      : SimpleThread("ThreadCallingShutdown"), tracker_(tracker) {}
 
   // Returns true once the async call to Shutdown() has returned.
-  bool has_returned() { return has_returned_.IsSignaled(); }
+  bool has_returned() { return has_returned_.IsSet(); }
 
  private:
   void Run() override {
     tracker_->Shutdown();
-    has_returned_.Signal();
+    has_returned_.Set();
   }
 
   TaskTracker* const tracker_;
-  WaitableEvent has_returned_;
+  AtomicFlag has_returned_;
 
   DISALLOW_COPY_AND_ASSIGN(ThreadCallingShutdown);
 };