Regularly poll the X11 event queue.

ui/events/platform/x11/x11_event_source.h

Index: ui/events/platform/x11/x11_event_source.h
diff --git a/ui/events/platform/x11/x11_event_source.h b/ui/events/platform/x11/x11_event_source.h
index d91fefe149b3da8bbd02adfa676cf128db8e21ae..2c3c4e399e334b3d4106c8028d7dec0d20dbe99c 100644
--- a/ui/events/platform/x11/x11_event_source.h
+++ b/ui/events/platform/x11/x11_event_source.h
@@ -28,9 +28,10 @@ class EVENTS_EXPORT X11EventSource : public PlatformEventSource {
 
   static X11EventSource* GetInstance();
 
-  // Called by the glib source dispatch function. Processes all (if any)
-  // available X events.
-  void DispatchXEvents();
+  // Processes pending X events.  Returns true if any events were dispatched.
+  // This function should be called repeatedly until it returns false to
+  // ensure all events are processed.
+  bool DispatchXEvents();
 
   // Blocks on the X11 event queue until we receive notification from the
   // xserver that |w| has been mapped; StructureNotifyMask events on |w| are
@@ -59,6 +60,9 @@ class EVENTS_EXPORT X11EventSource : public PlatformEventSource {
   // available events.
   bool continue_stream_;
 
+  // Dispatch one event at a time.
+  bool dispatch_one_event_per_loop_;
+
   scoped_ptr<X11HotplugEventHandler> hotplug_event_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(X11EventSource);