Manual refactor to enum-based WaitableEvent for remaining mac/ios files

ui/accelerated_widget_mac/window_resize_helper_mac.cc

Index: ui/accelerated_widget_mac/window_resize_helper_mac.cc
diff --git a/ui/accelerated_widget_mac/window_resize_helper_mac.cc b/ui/accelerated_widget_mac/window_resize_helper_mac.cc
index f44f7ae829df06511116a7b9a1bf1acb50e783e6..a3b61836abe1e0c149915897dcfff0b655c78fb0 100644
--- a/ui/accelerated_widget_mac/window_resize_helper_mac.cc
+++ b/ui/accelerated_widget_mac/window_resize_helper_mac.cc
@@ -175,7 +175,8 @@ void WrappedTask::RemoveFromTaskRunnerQueue() {
 PumpableTaskRunner::PumpableTaskRunner(
     const EventTimedWaitCallback& event_timed_wait_callback,
     const scoped_refptr<base::SingleThreadTaskRunner>& target_task_runner)
-    : event_(false /* auto-reset */, false /* initially signalled */),
+    : event_(base::WaitableEvent::ResetPolicy::AUTOMATIC,
+             base::WaitableEvent::InitialState::NOT_SIGNALED),
       event_timed_wait_callback_(event_timed_wait_callback),
       target_task_runner_(target_task_runner) {}