Fix out of order key events in Chrome on Linux.

chrome/browser/ui/libgtk2ui/gtk2_event_loop.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/libgtk2ui/gtk2_event_loop.h"
 
 #include <gdk/gdk.h>
 #include <gdk/gdkx.h>
 #include <gtk/gtk.h>
 #include <X11/X.h>
 
 #include "base/memory/singleton.h"
+#include "ui/events/platform/x11/x11_event_source.h"
 #include "ui/gfx/x/x11_types.h"
 
 namespace libgtk2ui {
 
 // static
 Gtk2EventLoop* Gtk2EventLoop::GetInstance() {
   return Singleton<Gtk2EventLoop>::get();
 }
 
 Gtk2EventLoop::Gtk2EventLoop() {
@@ skipping 40 matching lines @@
       gdk_event_key.type == GDK_KEY_PRESS ? KeyPress : KeyRelease;
   x_event.xkey.send_event = gdk_event_key.send_event;
   x_event.xkey.display = gfx::GetXDisplay();
   x_event.xkey.window = GDK_WINDOW_XID(gdk_event_key.window);
   x_event.xkey.root = DefaultRootWindow(x_event.xkey.display);
   x_event.xkey.time = gdk_event_key.time;
   x_event.xkey.state = gdk_event_key.state;
   x_event.xkey.keycode = gdk_event_key.hardware_keycode;
   x_event.xkey.same_screen = true;
 
-  XPutBackEvent(x_event.xkey.display, &x_event);
+  // We want to process the gtk2 event; mapped to an X11 event immediately
+  // otherwise if we put it back on the queue we may get items out of order.
+  if (ui::X11EventSource* x11_source = ui::X11EventSource::GetInstance())
+    x11_source->DispatchEventNow(&x_event);
+  else
+    XPutBackEvent(x_event.xkey.display, &x_event);

[sadrul, 2015/09/02 17:18:52]

Can we send this key-event directly to the InputMethod instead of going through
the event-source?

 }
 
 }  // namespace libgtk2ui