X11: Wait for UnmapNotify before trying to remap

ui/events/platform/x11/x11_event_source.cc

Index: ui/events/platform/x11/x11_event_source.cc
diff --git a/ui/events/platform/x11/x11_event_source.cc b/ui/events/platform/x11/x11_event_source.cc
index c9e5e15d5967b1f5afeb97802f73e308c216c841..3af94e3f76ed6e00050e49a34511e122c6e461fc 100644
--- a/ui/events/platform/x11/x11_event_source.cc
+++ b/ui/events/platform/x11/x11_event_source.cc
@@ -141,13 +141,11 @@ void X11EventSource::DispatchXEvents() {
 }
 
 void X11EventSource::BlockUntilWindowMapped(XID window) {
-  XEvent event;
-  do {
-    // Block until there's a message of |event_mask| type on |w|. Then remove
-    // it from the queue and stuff it in |event|.
-    XWindowEvent(display_, window, StructureNotifyMask, &event);
-    ExtractCookieDataDispatchEvent(&event);
-  } while (event.type != MapNotify);
+  BlockOnWindowStructureEvent(window, MapNotify);
+}
+
+void X11EventSource::BlockUntilWindowUnmapped(XID window) {
+  BlockOnWindowStructureEvent(window, UnmapNotify);
 }
 
 Time X11EventSource::UpdateLastSeenServerTime() {
@@ -225,6 +223,16 @@ void X11EventSource::PostDispatchEvent(XEvent* xevent) {
   }
 }
 
+void X11EventSource::BlockOnWindowStructureEvent(XID window, int type) {
+  XEvent event;
+  do {
+    // Block until there's a StructureNotify event of |type| on |window|. Then
+    // remove it from the queue and stuff it in |event|.
+    XWindowEvent(display_, window, StructureNotifyMask, &event);
+    ExtractCookieDataDispatchEvent(&event);
+  } while (event.type != type);
+}
+
 void X11EventSource::StopCurrentEventStream() {
   continue_stream_ = false;
 }