blob: 08a8bb0499f9073807886141df68c818889c944d [file] [log] [blame]
// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "android_webview/browser/aw_feature_list_creator.h"
#include <memory>
#include <set>
#include <string>
#include <utility>
#include <vector>
#include "android_webview/browser/aw_browser_context.h"
#include "android_webview/browser/aw_browser_process.h"
#include "android_webview/browser/aw_metrics_service_client.h"
#include "android_webview/browser/aw_variations_seed_bridge.h"
#include "base/base_switches.h"
#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/command_line.h"
#include "base/feature_list.h"
#include "base/path_service.h"
#include "base/strings/string_split.h"
#include "base/time/time.h"
#include "cc/base/switches.h"
#include "components/autofill/core/common/autofill_prefs.h"
#include "components/metrics/metrics_pref_names.h"
#include "components/metrics/metrics_service.h"
#include "components/pref_registry/pref_registry_syncable.h"
#include "components/prefs/in_memory_pref_store.h"
#include "components/prefs/json_pref_store.h"
#include "components/prefs/pref_registry_simple.h"
#include "components/prefs/pref_service.h"
#include "components/prefs/pref_service_factory.h"
#include "components/variations/entropy_provider.h"
#include "components/variations/pref_names.h"
#include "components/variations/service/safe_seed_manager.h"
#include "components/variations/service/variations_service.h"
#include "content/public/common/content_switch_dependent_feature_overrides.h"
#include "services/preferences/tracked/segregated_pref_store.h"
namespace android_webview {
namespace {
// These prefs go in the JsonPrefStore, and will persist across runs. Other
// prefs go in the InMemoryPrefStore, and will be lost when the process ends.
const char* const kPersistentPrefsWhitelist[] = {
// Randomly-generated GUID which pseudonymously identifies uploaded metrics.
metrics::prefs::kMetricsClientID,
// Random seed value for variation's entropy providers. Used to assign
// experiment groups.
metrics::prefs::kMetricsLowEntropySource,
// Current and past country codes, to filter variations studies by country.
variations::prefs::kVariationsCountry,
variations::prefs::kVariationsPermanentConsistencyCountry,
};
// Shows notifications which correspond to PersistentPrefStore's reading errors.
void HandleReadError(PersistentPrefStore::PrefReadError error) {}
base::FilePath GetPrefStorePath() {
base::FilePath path;
base::PathService::Get(base::DIR_ANDROID_APP_DATA, &path);
path = path.Append(FILE_PATH_LITERAL("pref_store"));
return path;
}
std::unique_ptr<PrefService> CreatePrefService() {
auto pref_registry = base::MakeRefCounted<user_prefs::PrefRegistrySyncable>();
metrics::MetricsService::RegisterPrefs(pref_registry.get());
variations::VariationsService::RegisterPrefs(pref_registry.get());
AwBrowserProcess::RegisterNetworkContextLocalStatePrefs(pref_registry.get());
PrefServiceFactory pref_service_factory;
std::set<std::string> persistent_prefs;
for (const char* const pref_name : kPersistentPrefsWhitelist)
persistent_prefs.insert(pref_name);
// SegregatedPrefStore may be validated with a MAC (message authentication
// code). On Android, the store is protected by app sandboxing, so validation
// is unnnecessary. Thus validation_delegate is null.
pref_service_factory.set_user_prefs(base::MakeRefCounted<SegregatedPrefStore>(
base::MakeRefCounted<InMemoryPrefStore>(),
base::MakeRefCounted<JsonPrefStore>(GetPrefStorePath()), persistent_prefs,
/*validation_delegate=*/nullptr));
pref_service_factory.set_read_error_callback(
base::BindRepeating(&HandleReadError));
return pref_service_factory.Create(pref_registry);
}
} // namespace
AwFeatureListCreator::AwFeatureListCreator()
: aw_field_trials_(std::make_unique<AwFieldTrials>()) {}
AwFeatureListCreator::~AwFeatureListCreator() {}
void AwFeatureListCreator::SetUpFieldTrials() {
auto* metrics_client = AwMetricsServiceClient::GetInstance();
// Chrome uses the default entropy provider here (rather than low entropy
// provider). The default provider needs to know whether UMA is enabled, but
// WebView determines UMA by querying GMS, which is very slow. So WebView
// always uses the low entropy provider. Both providers guarantee permanent
// consistency, which is the main requirement. The difference is that the low
// entropy provider has fewer unique experiment combinations. This is better
// for privacy (since experiment state doesn't identify users), but also means
// fewer combinations tested in the wild.
DCHECK(!field_trial_list_);
field_trial_list_ = std::make_unique<base::FieldTrialList>(
metrics_client->CreateLowEntropyProvider());
variations::UIStringOverrider ui_string_overrider;
client_ = std::make_unique<AwVariationsServiceClient>();
auto seed_store = std::make_unique<variations::VariationsSeedStore>(
local_state_.get(), /*initial_seed=*/GetAndClearJavaSeed(),
/*on_initial_seed_stored=*/base::DoNothing());
variations_field_trial_creator_ =
std::make_unique<variations::VariationsFieldTrialCreator>(
local_state_.get(), client_.get(), std::move(seed_store),
ui_string_overrider);
variations_field_trial_creator_->OverrideVariationsPlatform(
variations::Study::PLATFORM_ANDROID_WEBVIEW);
// Safe Mode is a feature which reverts to a previous variations seed if the
// current one is suspected to be causing crashes, or preventing new seeds
// from being downloaded. It's not implemented for WebView because 1) it's
// difficult for WebView to implement Safe Mode's crash detection, and 2)
// downloading and disseminating seeds is handled by the WebView service,
// which itself doesn't support variations; therefore a bad seed shouldn't be
// able to break seed downloads. See https://crbug.com/801771 for more info.
std::set<std::string> unforceable_field_trials;
variations::SafeSeedManager ignored_safe_seed_manager(true,
local_state_.get());
// Populate FieldTrialList. Since low_entropy_provider is null, it will fall
// back to the provider we previously gave to FieldTrialList, which is a low
// entropy provider.
variations_field_trial_creator_->SetupFieldTrials(
cc::switches::kEnableGpuBenchmarking, switches::kEnableFeatures,
switches::kDisableFeatures, unforceable_field_trials,
std::vector<std::string>(),
content::GetSwitchDependentFeatureOverrides(
*base::CommandLine::ForCurrentProcess()),
/*low_entropy_provider=*/nullptr, std::make_unique<base::FeatureList>(),
aw_field_trials_.get(), &ignored_safe_seed_manager);
}
void AwFeatureListCreator::CreateLocalState() {
browser_policy_connector_ = std::make_unique<AwBrowserPolicyConnector>();
local_state_ = CreatePrefService();
}
void AwFeatureListCreator::CreateFeatureListAndFieldTrials() {
CreateLocalState();
AwMetricsServiceClient::GetInstance()->Initialize(local_state_.get());
SetUpFieldTrials();
}
} // namespace android_webview