chromium/content/public/browser/preloading_data.h

// Copyright 2022 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_PUBLIC_BROWSER_PRELOADING_DATA_H_
#define CONTENT_PUBLIC_BROWSER_PRELOADING_DATA_H_

#include <optional>

#include "base/functional/callback.h"
#include "content/common/content_export.h"
#include "content/public/browser/preloading.h"
#include "services/metrics/public/cpp/ukm_source_id.h"
#include "url/gurl.h"

namespace content {

class WebContents;
class NavigationHandle;
PreloadingURLMatchCallback;
PredictorDomainCallback;

// PreloadingPrediction and PreloadingAttempt are the preloading logging APIs
// which allows us to set various metrics and log the values.

// All these metrics are logged into the UKM after the page navigates or when
// the WebContents is being destroyed. This API will be used by features both
// inside and outside //content.

// Both PreloadingPrediction and PreloadingAttempt are owned by PreloadingData
// class and that is associated with WebContentsUserData. PreloadingAttempt is
// cleared when either
// - A WebContents is deleted/ destroyed.
// - Primary page of the WebContents changes.

// PreloadingAttempt keeps track of every preloading attempt associated with
// various preloading features defined in preloading.h (please see the comments
// there for more details); whether it is eligible, whether it is triggered or
// not, specifies the failure reason on failing and others.
class CONTENT_EXPORT PreloadingAttempt { … };

// PreloadingData holds the data associated with all the PreloadingAttempts
// and PreloadingPredictions. This class is responsible for notifying all the
// PreloadingAttempts and PreloadingPredictions about logging the UKMs and
// maintaining its lifetime.

// Lifetime of PreloadingData is associated with WebContentsUserData.
class CONTENT_EXPORT PreloadingData { … };

}  // namespace content

#endif  // CONTENT_PUBLIC_BROWSER_PRELOADING_DATA_H_