Migrate WaitableEvent to enum-based constructor in base/

base/message_loop/message_pump_default.cc

Index: base/message_loop/message_pump_default.cc
diff --git a/base/message_loop/message_pump_default.cc b/base/message_loop/message_pump_default.cc
index ed15395d56f050f95183eb8502c6e9953f747fe0..0fac8b3c9c9adbe7597b59096a30ba2a9ad7e935 100644
--- a/base/message_loop/message_pump_default.cc
+++ b/base/message_loop/message_pump_default.cc
@@ -16,8 +16,8 @@ namespace base {
 
 MessagePumpDefault::MessagePumpDefault()
     : keep_running_(true),
-      event_(false, false) {
-}
+      event_(WaitableEvent::ResetPolicy::AUTOMATIC,
+             WaitableEvent::InitialState::NOT_SIGNALED) {}
 
 MessagePumpDefault::~MessagePumpDefault() {
 }