Move X11 device processing to worker threads

ui/events/platform/x11/x11_event_source.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 "ui/events/platform/x11/x11_event_source.h"
 
 #include <X11/extensions/XInput2.h>
 #include <X11/X.h>
 #include <X11/Xlib.h>
 #include <X11/XKBlib.h>
@@ skipping 68 matching lines @@
   return true;
 }
 
 }  // namespace
 
 X11EventSource::X11EventSource(XDisplay* display)
     : display_(display),
       continue_stream_(true) {
   CHECK(display_);
   DeviceDataManagerX11::CreateInstance();
-  hotplug_event_handler_.reset(
-      new X11HotplugEventHandler(DeviceDataManager::GetInstance()));
   InitializeXInput2(display_);
   InitializeXkb(display_);
-
-  // Force the initial device query to have an update list of active devices.
-  hotplug_event_handler_->OnHotplugEvent();
 }
 
 X11EventSource::~X11EventSource() {
 }
 
 // static
 X11EventSource* X11EventSource::GetInstance() {
   return static_cast<X11EventSource*>(PlatformEventSource::GetInstance());
 }
 
@@ skipping 42 matching lines @@
 
   if (have_cookie)
     XFreeEventData(xevent->xgeneric.display, &xevent->xcookie);
   return action;
 }
 
 void X11EventSource::StopCurrentEventStream() {
   continue_stream_ = false;
 }
 
+void X11EventSource::OnDispatcherListChanged() {
+  if (!hotplug_event_handler_) {
+    hotplug_event_handler_.reset(new X11HotplugEventHandler());
+    // Force the initial device query to have an update list of active devices.
+    hotplug_event_handler_->OnHotplugEvent();
+  }
+}
+
 }  // namespace ui