1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
|
// Copyright 2020 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_VISIBILITY_TIMER_TAB_HELPER_H_
#define CHROME_BROWSER_VISIBILITY_TIMER_TAB_HELPER_H_
#include "base/containers/circular_deque.h"
#include "base/functional/callback_forward.h"
#include "base/timer/timer.h"
#include "content/public/browser/web_contents_observer.h"
#include "content/public/browser/web_contents_user_data.h"
// At most one of these is attached to each WebContents. It allows posting
// delayed tasks whose timer only counts down whilst the WebContents is visible
// (and whose timer is reset whenever the WebContents stops being visible).
// If multiple tasks are added, they are queued in a dormant state -- their
// timer will not elapse until earlier tasks are completed.
class VisibilityTimerTabHelper
: public content::WebContentsObserver,
public content::WebContentsUserData<VisibilityTimerTabHelper> {
public:
VisibilityTimerTabHelper(const VisibilityTimerTabHelper&&) = delete;
VisibilityTimerTabHelper& operator=(const VisibilityTimerTabHelper&&) =
delete;
~VisibilityTimerTabHelper() override;
// Runs |task| after the WebContents has been visible for a consecutive
// duration of at least |visible_delay|.
void PostTaskAfterVisibleDelay(const base::Location& from_here,
base::OnceClosure task,
base::TimeDelta visible_delay);
// WebContentsObserver:
void OnVisibilityChanged(content::Visibility visibility) override;
private:
struct Task;
friend class content::WebContentsUserData<VisibilityTimerTabHelper>;
explicit VisibilityTimerTabHelper(content::WebContents* contents);
void RunTask(base::OnceClosure task);
void StartNextTaskTimer();
base::OneShotTimer timer_;
base::circular_deque<Task> task_queue_;
WEB_CONTENTS_USER_DATA_KEY_DECL();
};
#endif // CHROME_BROWSER_VISIBILITY_TIMER_TAB_HELPER_H_
|
