Explicitly coerce PostDispatchAction to uint32_t in DispatchEvent()

ui/events/platform/platform_event_source.h

Index: ui/events/platform/platform_event_source.h
diff --git a/ui/events/platform/platform_event_source.h b/ui/events/platform/platform_event_source.h
index 87b553197a3b2646d3c6eb035a640c6ae96a6385..e6c942376ec27ba6e3a2268073354464faf65c12 100644
--- a/ui/events/platform/platform_event_source.h
+++ b/ui/events/platform/platform_event_source.h
@@ -42,7 +42,7 @@ class EVENTS_EXPORT PlatformEventSource {
 
   // Installs a PlatformEventDispatcher that receives all the events. The
   // dispatcher can process the event, or request that the default dispatchers
-  // be invoked by setting |POST_DISPATCH_PERFORM_DEFAULT| flag from the
+  // be invoked by setting |kPostDispatchPerformDefault| flag from the
   // |DispatchEvent()| override.
   // The returned |ScopedEventDispatcher| object is a handler for the overridden
   // dispatcher. When this handler is destroyed, it removes the overridden