Migrate WaitableEvent to enum-based constructor in base/

base/allocator/allocator_shim_unittest.cc

Index: base/allocator/allocator_shim_unittest.cc
diff --git a/base/allocator/allocator_shim_unittest.cc b/base/allocator/allocator_shim_unittest.cc
index e61dd73af7f4f992ac7393f4e333a7339302e1d5..e1a7f53874ea6e472f34d3cbac1c80ae00061e85 100644
--- a/base/allocator/allocator_shim_unittest.cc
+++ b/base/allocator/allocator_shim_unittest.cc
@@ -301,7 +301,8 @@ TEST_F(AllocatorShimTest, NewHandlerConcurrency) {
 
   // The WaitableEvent here is used to attempt to trigger all the threads at
   // the same time, after they have been initialized.
-  WaitableEvent event(/*manual_reset=*/true, /*initially_signaled=*/false);
+  WaitableEvent event(WaitableEvent::ResetPolicy::MANUAL,
+                      WaitableEvent::InitialState::NOT_SIGNALED);
 
   ThreadDelegateForNewHandlerTest mock_thread_main(&event);