chromium/content/browser/scheduler/responsiveness/native_event_observer.h

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_SCHEDULER_RESPONSIVENESS_NATIVE_EVENT_OBSERVER_H_
#define CONTENT_BROWSER_SCHEDULER_RESPONSIVENESS_NATIVE_EVENT_OBSERVER_H_

#include <vector>

#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "build/build_config.h"
#include "content/common/content_export.h"

#if BUILDFLAG(IS_MAC)
#include "content/public/browser/native_event_processor_observer_mac.h"
#endif

#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
#include "ui/aura/window_event_dispatcher_observer.h"
#endif

#if BUILDFLAG(IS_WIN)
#include "base/message_loop/message_pump_win.h"
#endif

namespace content {
namespace responsiveness {

// This class must only be used from the UI thread.
//
// This class hooks itself into the native event processor for the platform and
// forwards will_run/did_run callbacks to Watcher. Native events are processed
// at different layers for each platform, so the interface for this class is
// necessarily messy.
//
// On macOS, the hook should be in -[BrowserCrApplication sendEvent:].
// On Linux, the hook should be in ui::PlatformEventSource::DispatchEvent.
// On Windows, the hook should be in MessagePumpForUI::ProcessMessageHelper.
// On Android, the hook should be in <TBD>.
class CONTENT_EXPORT NativeEventObserver
#if BUILDFLAG(IS_MAC)
    : public NativeEventProcessorObserver
#elif BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
    : public aura::WindowEventDispatcherObserver
#elif BUILDFLAG(IS_WIN)
    : public base::MessagePumpForUI::Observer
#endif
{ … };

}  // namespace responsiveness
}  // namespace content

#endif  // CONTENT_BROWSER_SCHEDULER_RESPONSIVENESS_NATIVE_EVENT_OBSERVER_H_