ui/events/platform/platform_event_observer.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_EVENTS_PLATFORM_PLATFORM_EVENT_OBSERVER_H_
   6 #define UI_EVENTS_PLATFORM_PLATFORM_EVENT_OBSERVER_H_
   7
   8 #include "ui/events/events_export.h"
   9 #include "ui/events/platform/platform_event_types.h"
  10
  11 namespace ui {
  12
  13 // PlatformEventObserver can be installed on a PlatformEventSource, and it
  14 // receives all events that are dispatched to the dispatchers.
  15 class EVENTS_EXPORT PlatformEventObserver {
  16  public:
  17   // This is called before the dispatcher receives the event.
  18   virtual void WillProcessEvent(const PlatformEvent& event) = 0;
  19
  20   // This is called after the event has been dispatched to the dispatcher(s).
  21   virtual void DidProcessEvent(const PlatformEvent& event) = 0;
  22
  23  protected:
  24   virtual ~PlatformEventObserver() {}
  25 };
  26
  27 }  // namespace ui
  28
  29 #endif  // UI_EVENTS_PLATFORM_PLATFORM_EVENT_OBSERVER_H_