mash: Fix mash in debug builds.

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/Xatom.h>
 #include <X11/XKBlib.h>
 #include <X11/Xlib.h>
 
@@ skipping 96 matching lines @@
   InitializeXkb(display_);
 }
 
 X11EventSource::~X11EventSource() {
   DCHECK_EQ(this, instance_);
   instance_ = nullptr;
   if (dummy_initialized_)
     XDestroyWindow(display_, dummy_window_);
 }
 
+bool X11EventSource::HasInstance() {
+  return instance_;
+}
+
 // static
 X11EventSource* X11EventSource::GetInstance() {
   DCHECK(instance_);
   return instance_;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // X11EventSource, public
 
 void X11EventSource::DispatchXEvents() {
@@ skipping 100 matching lines @@
 
 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