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// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/child/field_trial.h"
#include <tuple>
#include "base/base_switches.h"
#include "base/command_line.h"
#include "base/debug/leak_annotations.h"
#include "base/feature_list.h"
#include "base/metrics/field_trial.h"
#include "base/metrics/histogram_shared_memory.h"
#include "build/build_config.h"
#include "content/public/common/content_descriptors.h"
#include "content/public/common/content_switch_dependent_feature_overrides.h"
#include "content/public/common/content_switches.h"
namespace content {
void InitializeFieldTrialAndFeatureList() {
const base::CommandLine& command_line =
*base::CommandLine::ForCurrentProcess();
base::HistogramSharedMemory::InitFromLaunchParameters(command_line);
// Initialize statistical testing infrastructure.
//
// This is intentionally leaked since it needs to live for the duration of the
// process and there's no benefit in cleaning it up at exit.
base::FieldTrialList* leaked_field_trial_list = new base::FieldTrialList();
ANNOTATE_LEAKING_OBJECT_PTR(leaked_field_trial_list);
std::ignore = leaked_field_trial_list;
// Ensure any field trials in browser are reflected into the child process.
base::FieldTrialList::CreateTrialsInChildProcess(command_line);
std::unique_ptr<base::FeatureList> feature_list(new base::FeatureList);
base::FieldTrialList::ApplyFeatureOverridesInChildProcess(feature_list.get());
// TODO(crbug.com/40638048): This may be redundant. The way this is supposed
// to work is that the parent process's state should be passed via
// command-line to the child process, such that a feature explicitly enabled
// or disabled in the parent process via this mechanism (since the browser
// process also registers these switch-dependent overrides), it will get
// passed via the command line - so then no extra logic would be needed in the
// child.
// TODO(chlily): Test this more thoroughly and understand the behavior to see
// whether this is actually needed.
feature_list->RegisterExtraFeatureOverrides(
GetSwitchDependentFeatureOverrides(command_line));
base::FeatureList::SetInstance(std::move(feature_list));
}
} // namespace content
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