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// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CHROME_BROWSER_CHAINED_BACK_NAVIGATION_TRACKER_H_
#define CHROME_BROWSER_CHAINED_BACK_NAVIGATION_TRACKER_H_
#include "base/gtest_prod_util.h"
#include "content/public/browser/web_contents_observer.h"
#include "content/public/browser/web_contents_user_data.h"
// This class tracks chained back navigations (consecutive back navigations with
// a short interval between them) by observing navigation events from
// WebContents and providing functions to record back button clicks.
class ChainedBackNavigationTracker
: public content::WebContentsObserver,
public content::WebContentsUserData<ChainedBackNavigationTracker> {
public:
~ChainedBackNavigationTracker() override;
ChainedBackNavigationTracker(const ChainedBackNavigationTracker&) = delete;
ChainedBackNavigationTracker& operator=(const ChainedBackNavigationTracker&) =
delete;
// content::WebContentsObserver
void DidStartNavigation(content::NavigationHandle* navigation) override;
// Notifies the `ChainedBackNavigationTracker` that a back/forward button is
// clicked. This will be used to determined if a chained back navigation is
// performed by back button.
void RecordBackButtonClickForChainedBackNavigation();
// The two functions below should be called to determine if the relevant user
// education promotion (such as the one for back navigation menu) should be
// displayed according to the corresponding trigger condition.
// Returns if a chained back/forward navigation is performed no earlier that
// the `kMaxChainedBackNavigationIntervalInMilliseconds` ago.
bool IsChainedBackNavigationRecentlyPerformed() const;
// Returns if a chained back button click events that caused chained back
// navigation is performed no earlier than the
// `kMaxChainedBackNavigationIntervalInMilliseconds` ago.
bool IsBackButtonChainedBackNavigationRecentlyPerformed() const;
// The threshold for two back/forward navigation to be considered chained.
static const int64_t kMaxChainedBackNavigationIntervalInMilliseconds = 3000;
// The minimum number of back/forward navigations in a chain for the
// `ChainedBackNavigationTracker` to claim that a chained back navigation is
// performed.
static const uint32_t kMinimumChainedBackNavigationLength = 3u;
private:
friend class content::WebContentsUserData<ChainedBackNavigationTracker>;
FRIEND_TEST_ALL_PREFIXES(
ChainedBackNavigationTrackerTest,
ChainedBackNavigationStatus_ResetCountIfNonBackForwardNavigationHappens);
FRIEND_TEST_ALL_PREFIXES(ChainedBackNavigationTrackerBrowserTest,
SubframeBackNavigationIsCountedAsChained);
FRIEND_TEST_ALL_PREFIXES(
ChainedBackNavigationTrackerBrowserTest,
RendererInitiatedBackNavigationIsNotCountedAsChained);
explicit ChainedBackNavigationTracker(content::WebContents* contents);
// Helper functions that modify the `last_back_navigation_time_` and
// `chained_back_navigation_count_`.
// The chained back navigation count should increment when a back/forward
// navigation is performed and the interval between the current time tick and
// the last recorded time tick is smaller than the threshold.
void IncrementChainedBackNavigationCount();
// The chained back navigation count should be reset to 0 if a
// non-back/forward navigation is performed.
void ResetChainedBackNavigationCount();
// Chained back navigation variables that are used to record the number of
// consecutive back navigation and back button click events with interval
// shorter than some threshold.
uint32_t chained_back_navigation_count_ = 0;
uint32_t chained_back_button_click_count_ = 0;
base::TimeTicks last_back_navigation_time_;
base::TimeTicks last_back_button_click_time_;
WEB_CONTENTS_USER_DATA_KEY_DECL();
};
#endif // CHROME_BROWSER_CHAINED_BACK_NAVIGATION_TRACKER_H_
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