Bug 1592502 initialize all fields of GdkEvents r=stransky

Differential Revision: https://phabricator.services.mozilla.com/D51051

--HG--
extra : moz-landing-system : lando

widget/gtk/nsClipboardX11.cpp

@@ -81,7 +81,7 @@ nsRetrievalContextX11::~nsRetrievalContextX11() {
 }
 
 static void DispatchSelectionNotifyEvent(GtkWidget* widget, XEvent* xevent) {
-  GdkEvent event;
+  GdkEvent event = {};
   event.selection.type = GDK_SELECTION_NOTIFY;
   event.selection.window = gtk_widget_get_window(widget);
   event.selection.selection =
@@ -96,7 +96,7 @@ static void DispatchSelectionNotifyEvent(GtkWidget* widget, XEvent* xevent) {
 static void DispatchPropertyNotifyEvent(GtkWidget* widget, XEvent* xevent) {
   GdkWindow* window = gtk_widget_get_window(widget);
   if ((gdk_window_get_events(window)) & GDK_PROPERTY_CHANGE_MASK) {
-    GdkEvent event;
+    GdkEvent event = {};
     event.property.type = GDK_PROPERTY_NOTIFY;
     event.property.window = window;
     event.property.atom = gdk_x11_xatom_to_atom(xevent->xproperty.atom);