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
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
|
// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/variations/child_process_field_trial_syncer.h"
#include <utility>
#include "base/auto_reset.h"
#include "base/base_switches.h"
#include "base/command_line.h"
#include "base/containers/contains.h"
#include "base/metrics/field_trial_list_including_low_anonymity.h"
#include "components/variations/variations_crash_keys.h"
namespace variations {
namespace {
ChildProcessFieldTrialSyncer* g_instance = nullptr;
constinit thread_local bool in_set_field_trial_group_from_browser = false;
} // namespace
// static
ChildProcessFieldTrialSyncer* ChildProcessFieldTrialSyncer::CreateInstance(
FieldTrialActivatedCallback activated_callback) {
CHECK(!g_instance);
g_instance = new ChildProcessFieldTrialSyncer(std::move(activated_callback));
g_instance->Init(base::FieldTrialList::GetActiveTrialsOfParentProcess());
return g_instance;
}
// static
ChildProcessFieldTrialSyncer*
ChildProcessFieldTrialSyncer::CreateInstanceForTesting(
const std::set<std::string>& initially_active_trials,
FieldTrialActivatedCallback activated_callback) {
CHECK(!g_instance);
g_instance = new ChildProcessFieldTrialSyncer(std::move(activated_callback));
g_instance->Init(initially_active_trials);
return g_instance;
}
// static
void ChildProcessFieldTrialSyncer::DeleteInstanceForTesting() {
CHECK(g_instance);
delete g_instance;
g_instance = nullptr;
// Revert the effect of calling variations::InitCrashKeys() in Init().
ClearCrashKeysInstanceForTesting(); // IN-TEST
}
ChildProcessFieldTrialSyncer::ChildProcessFieldTrialSyncer(
FieldTrialActivatedCallback activated_callback)
: activated_callback_(std::move(activated_callback)) {}
ChildProcessFieldTrialSyncer::~ChildProcessFieldTrialSyncer() = default;
void ChildProcessFieldTrialSyncer::Init(
const std::set<std::string>& initially_active_trials) {
// Set up initial set of crash dump data for field trials in this process.
variations::InitCrashKeys();
// Listen for field trial activations to report them to the browser.
// All trials (including low anonymity ones) are required so that the browser
// and child processes have a consistent view.
//
// See also TODO(crbug.com/40263398) at
// |FieldTrialSynchronizer::FieldTrialSynchronizer()|.
base::FieldTrialListIncludingLowAnonymity::AddObserver(this);
// Some field trials may have been activated before this point. Notify the
// browser of these activations now. To detect these, take the set difference
// of currently active trials with the initially active trials.
base::FieldTrial::ActiveGroups current_active_trials;
base::FieldTrialListIncludingLowAnonymity::GetActiveFieldTrialGroups(
¤t_active_trials);
for (const auto& trial : current_active_trials) {
if (!base::Contains(initially_active_trials, trial.trial_name)) {
activated_callback_.Run(trial.trial_name);
}
}
}
void ChildProcessFieldTrialSyncer::SetFieldTrialGroupFromBrowser(
const std::string& trial_name,
const std::string& group_name) {
const base::AutoReset<bool> resetter(&in_set_field_trial_group_from_browser,
true, false);
base::FieldTrial* trial =
base::FieldTrialList::CreateFieldTrial(trial_name, group_name);
// Ensure the trial is marked as "used" by calling Activate() on it if it is
// marked as activated.
trial->Activate();
}
void ChildProcessFieldTrialSyncer::OnFieldTrialGroupFinalized(
const base::FieldTrial& trial,
const std::string& group_name) {
// It is not necessary to notify the browser if this is invoked from
// SetFieldTrialGroupFromBrowser().
if (!in_set_field_trial_group_from_browser) {
activated_callback_.Run(trial.trial_name());
}
}
} // namespace variations
|
