Migrate WaitableEvent to enum-based constructor in sync/

sync/test/fake_server/fake_server_http_post_provider.cc

Index: sync/test/fake_server/fake_server_http_post_provider.cc
diff --git a/sync/test/fake_server/fake_server_http_post_provider.cc b/sync/test/fake_server/fake_server_http_post_provider.cc
index 7a844b9900c569b2cdd7f6b48b38e631e9e535d7..55666794deac507d08ee6f6efedee3de882ec905 100644
--- a/sync/test/fake_server/fake_server_http_post_provider.cc
+++ b/sync/test/fake_server/fake_server_http_post_provider.cc
@@ -75,7 +75,9 @@ bool FakeServerHttpPostProvider::MakeSynchronousPost(int* error_code,
   int post_response_code = -1;
   std::string post_response;
 
-  base::WaitableEvent post_complete(false, false);
+  base::WaitableEvent post_complete(
+      base::WaitableEvent::ResetPolicy::AUTOMATIC,
+      base::WaitableEvent::InitialState::NOT_SIGNALED);
   base::Closure signal_closure = base::Bind(&base::WaitableEvent::Signal,
                                             base::Unretained(&post_complete));