Make WaitableEventWatcher TaskScheduler-friendly.

base/synchronization/waitable_event_watcher_unittest.cc

Index: base/synchronization/waitable_event_watcher_unittest.cc
diff --git a/base/synchronization/waitable_event_watcher_unittest.cc b/base/synchronization/waitable_event_watcher_unittest.cc
index 94e5ff42a8388dc8bf7082c7cf3e65e0ba599477..fcb4257d6df218b5a14b81f954fbf7f7b73201b6 100644
--- a/base/synchronization/waitable_event_watcher_unittest.cc
+++ b/base/synchronization/waitable_event_watcher_unittest.cc
@@ -52,16 +52,11 @@ void RunTest_BasicSignal(MessageLoop::Type message_loop_type) {
                       WaitableEvent::InitialState::NOT_SIGNALED);
 
   WaitableEventWatcher watcher;
-  EXPECT_TRUE(watcher.GetWatchedEvent() == NULL);
-
   watcher.StartWatching(&event, Bind(&QuitWhenSignaled));
-  EXPECT_EQ(&event, watcher.GetWatchedEvent());
 
   event.Signal();
 
   RunLoop().Run();
-
-  EXPECT_TRUE(watcher.GetWatchedEvent() == NULL);
 }
 
 void RunTest_BasicCancel(MessageLoop::Type message_loop_type) {