Delete the property returned by SelectionNotify as per ICCCM spec

ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc

Index: ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc
diff --git a/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc b/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc
index 9dc300b2632ac155947935eea641a16591669dec..7488339535a833037731364a6e283cbcbfa7cc4a 100644
--- a/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc
+++ b/ui/views/widget/desktop_aura/desktop_drag_drop_client_aurax11.cc
@@ -621,12 +621,12 @@ void DesktopDragDropClientAuraX11::OnXdndDrop(
 
 void DesktopDragDropClientAuraX11::OnSelectionNotify(
     const XSelectionEvent& xselection) {
-  if (!target_current_context_) {
-    NOTIMPLEMENTED();
-    return;
-  }
+  if (target_current_context_)
+    target_current_context_->OnSelectionNotify(xselection);
 
-  target_current_context_->OnSelectionNotify(xselection);
+  // ICCCM requires us to delete the property passed into SelectionNotify.
+  if (xselection.property != None)
+    XDeleteProperty(xdisplay_, xwindow_, xselection.property);
 }
 
 int DesktopDragDropClientAuraX11::StartDragAndDrop(