chromium/content/browser/renderer_host/visible_time_request_trigger.h

// Copyright 2021 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_RENDERER_HOST_VISIBLE_TIME_REQUEST_TRIGGER_H_
#define CONTENT_BROWSER_RENDERER_HOST_VISIBLE_TIME_REQUEST_TRIGGER_H_

#include "content/common/content_export.h"
#include "third_party/blink/public/mojom/widget/record_content_to_visible_time_request.mojom.h"

namespace base {
class TimeTicks;
}  // namespace base

namespace content {

// Records the time of an event that will make a WebContents become visible,
// and the reason it will become visible. This time will be passed to the
// compositor and used to calculate the latency before the visible WebContents
// appears.
//
// This class holds a single RecordContentToVisibleTimeRequestPtr that is
// modified whenever UpdateRequest is called, and cleared whenever TakeRequest
// is called. This means that calling UpdateRequest for multiple overlapping
// events without calling TakeRequest in between will record metrics for all
// events using the same timestamps instead of tracking each event separately.
//
// TODO(crbug.com/40203057): Stop doing that. There should be a separate start
// time for each event.
class CONTENT_EXPORT VisibleTimeRequestTrigger { … };

}  // namespace content

#endif  // CONTENT_BROWSER_RENDERER_HOST_VISIBLE_TIME_REQUEST_TRIGGER_H_