mash: Fix mash in debug builds.

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>
@@ skipping 25 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(X11EventSourceDelegate);
 };
 
 // Receives X11 events and sends them to X11EventSourceDelegate. Handles
 // receiving, pre-process and post-processing XEvents.
 class EVENTS_EXPORT X11EventSource {
  public:
   X11EventSource(X11EventSourceDelegate* delegate, XDisplay* display);
   ~X11EventSource();
 
+  static bool HasInstance();
+
   static X11EventSource* GetInstance();
 
   // Called when there is a new XEvent available. Processes all (if any)
   // available X events.
   void DispatchXEvents();
 
   // Blocks on the X11 event queue until we receive notification from the
   // xserver that |w| has been mapped; StructureNotifyMask events on |w| are
   // pulled out from the queue and dispatched out of order.
   //
@@ skipping 44 matching lines @@
   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_