X11: Reset dispatching event when nested message loop ends

ui/events/platform/x11/x11_event_source.h

 // 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.
 
 #ifndef UI_EVENTS_PLATFORM_X11_X11_EVENT_SOURCE_H_
 #define UI_EVENTS_PLATFORM_X11_X11_EVENT_SOURCE_H_
 
 #include <stdint.h>
 
 #include <memory>
-#include <stack>
 
 #include "base/macros.h"
 #include "base/optional.h"
 #include "ui/events/events_export.h"
 #include "ui/gfx/x/x11_types.h"
 
 using Time = unsigned long;
 using XEvent = union _XEvent;
 using XID = unsigned long;
 using XWindow = unsigned long;
@@ skipping 86 matching lines @@
   Time GetCurrentServerTime();
 
  private:
   static X11EventSource* instance_;
 
   X11EventSourceDelegate* delegate_;
 
   // The connection to the X11 server used to receive the events.
   XDisplay* display_;
 
-  // Events currently being dispatched.  The topmost event in this stack
-  // corresponds to the deepest-nested message loop.
-  std::stack<XEvent*> dispatching_events_;
+  // Event currently being dispatched.
+  XEvent* dispatching_event_;
 
   // State necessary for UpdateLastSeenServerTime
   bool dummy_initialized_;
   XWindow dummy_window_;
   XAtom dummy_atom_;
   std::unique_ptr<XScopedEventSelector> dummy_window_events_;
 
   // Keeps track of whether this source should continue to dispatch all the
   // available events.
   bool continue_stream_ = true;
 
   std::unique_ptr<X11HotplugEventHandler> hotplug_event_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(X11EventSource);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_PLATFORM_X11_X11_EVENT_SOURCE_H_