Explicitly coerce PostDispatchAction to uint32_t in DispatchEvent()

ui/base/dragdrop/os_exchange_data_provider_aurax11.cc

Index: ui/base/dragdrop/os_exchange_data_provider_aurax11.cc
diff --git a/ui/base/dragdrop/os_exchange_data_provider_aurax11.cc b/ui/base/dragdrop/os_exchange_data_provider_aurax11.cc
index 714069fecd9e52bde99ef0427ba837a02d5bfd7a..f8cfc15735411fe03f196916c4f8fd5f1baa42c6 100644
--- a/ui/base/dragdrop/os_exchange_data_provider_aurax11.cc
+++ b/ui/base/dragdrop/os_exchange_data_provider_aurax11.cc
@@ -518,11 +518,11 @@ uint32_t OSExchangeDataProviderAuraX11::DispatchEvent(
   switch (xev->type) {
     case SelectionRequest:
       selection_owner_.OnSelectionRequest(*xev);
-      return ui::POST_DISPATCH_STOP_PROPAGATION;
+      return ui::kPostDispatchStopPropagation;
     default:
       NOTIMPLEMENTED();
   }
-  return ui::POST_DISPATCH_NONE;
+  return ui::kPostDispatchNone;
 }
 
 bool OSExchangeDataProviderAuraX11::GetPlainTextURL(GURL* url) const {