Make WaitableEvent's constructor enum-based.

base/synchronization/waitable_event_win.cc

Index: base/synchronization/waitable_event_win.cc
diff --git a/base/synchronization/waitable_event_win.cc b/base/synchronization/waitable_event_win.cc
index 89ace19961a7e7e42bca88e2f0a3663a2e30e763..d16ba6243a6ed6c5e5a48cd9f43ccffd5ebf2bdb 100644
--- a/base/synchronization/waitable_event_win.cc
+++ b/base/synchronization/waitable_event_win.cc
@@ -16,6 +16,11 @@
 
 namespace base {
 
+WaitableEvent::WaitableEvent(ResetPolicy reset_policy,
+                             InitialState initial_state)
+    : WaitableEvent(reset_policy == ResetPolicy::MANUAL,
+                    initial_state == InitialState::SIGNALED) {}
+
 WaitableEvent::WaitableEvent(bool manual_reset, bool signaled)
     : handle_(CreateEvent(NULL, manual_reset, signaled, NULL)) {
   // We're probably going to crash anyways if this is ever NULL, so we might as