blob: aae1bc6018971a3542be8638a4fb6c1b482e9bd7 [file] [log] [blame]
// Copyright 2015 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 "base/feature_list.h"
#include <algorithm>
#include <utility>
#include "base/format_macros.h"
#include "base/macros.h"
#include "base/memory/ptr_util.h"
#include "base/metrics/field_trial.h"
#include "base/metrics/persistent_memory_allocator.h"
#include "base/strings/string_piece.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "starboard/types.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
namespace {
constexpr char kFeatureOnByDefaultName[] = "OnByDefault";
struct Feature kFeatureOnByDefault {
kFeatureOnByDefaultName, FEATURE_ENABLED_BY_DEFAULT
};
constexpr char kFeatureOffByDefaultName[] = "OffByDefault";
struct Feature kFeatureOffByDefault {
kFeatureOffByDefaultName, FEATURE_DISABLED_BY_DEFAULT
};
std::string SortFeatureListString(const std::string& feature_list) {
std::vector<base::StringPiece> features =
FeatureList::SplitFeatureListString(feature_list);
std::sort(features.begin(), features.end());
return JoinString(features, ",");
}
} // namespace
class FeatureListTest : public testing::Test {
public:
FeatureListTest() : feature_list_(nullptr) {
RegisterFeatureListInstance(WrapUnique(new FeatureList));
}
~FeatureListTest() override { ClearFeatureListInstance(); }
void RegisterFeatureListInstance(std::unique_ptr<FeatureList> feature_list) {
FeatureList::ClearInstanceForTesting();
feature_list_ = feature_list.get();
FeatureList::SetInstance(std::move(feature_list));
}
void ClearFeatureListInstance() {
FeatureList::ClearInstanceForTesting();
feature_list_ = nullptr;
}
FeatureList* feature_list() { return feature_list_; }
private:
// Weak. Owned by the FeatureList::SetInstance().
FeatureList* feature_list_;
DISALLOW_COPY_AND_ASSIGN(FeatureListTest);
};
TEST_F(FeatureListTest, DefaultStates) {
EXPECT_TRUE(FeatureList::IsEnabled(kFeatureOnByDefault));
EXPECT_FALSE(FeatureList::IsEnabled(kFeatureOffByDefault));
}
TEST_F(FeatureListTest, InitializeFromCommandLine) {
struct {
const char* enable_features;
const char* disable_features;
bool expected_feature_on_state;
bool expected_feature_off_state;
} test_cases[] = {
{"", "", true, false},
{"OffByDefault", "", true, true},
{"OffByDefault", "OnByDefault", false, true},
{"OnByDefault,OffByDefault", "", true, true},
{"", "OnByDefault,OffByDefault", false, false},
// In the case an entry is both, disable takes precedence.
{"OnByDefault", "OnByDefault,OffByDefault", false, false},
};
for (size_t i = 0; i < arraysize(test_cases); ++i) {
const auto& test_case = test_cases[i];
SCOPED_TRACE(base::StringPrintf("Test[%" PRIuS "]: [%s] [%s]", i,
test_case.enable_features,
test_case.disable_features));
ClearFeatureListInstance();
std::unique_ptr<FeatureList> feature_list(new FeatureList);
feature_list->InitializeFromCommandLine(test_case.enable_features,
test_case.disable_features);
RegisterFeatureListInstance(std::move(feature_list));
EXPECT_EQ(test_case.expected_feature_on_state,
FeatureList::IsEnabled(kFeatureOnByDefault))
<< i;
EXPECT_EQ(test_case.expected_feature_off_state,
FeatureList::IsEnabled(kFeatureOffByDefault))
<< i;
}
}
TEST_F(FeatureListTest, CheckFeatureIdentity) {
// Tests that CheckFeatureIdentity() correctly detects when two different
// structs with the same feature name are passed to it.
// Call it twice for each feature at the top of the file, since the first call
// makes it remember the entry and the second call will verify it.
EXPECT_TRUE(feature_list()->CheckFeatureIdentity(kFeatureOnByDefault));
EXPECT_TRUE(feature_list()->CheckFeatureIdentity(kFeatureOnByDefault));
EXPECT_TRUE(feature_list()->CheckFeatureIdentity(kFeatureOffByDefault));
EXPECT_TRUE(feature_list()->CheckFeatureIdentity(kFeatureOffByDefault));
// Now, call it with a distinct struct for |kFeatureOnByDefaultName|, which
// should return false.
struct Feature kFeatureOnByDefault2 {
kFeatureOnByDefaultName, FEATURE_ENABLED_BY_DEFAULT
};
EXPECT_FALSE(feature_list()->CheckFeatureIdentity(kFeatureOnByDefault2));
}
TEST_F(FeatureListTest, FieldTrialOverrides) {
struct {
FeatureList::OverrideState trial1_state;
FeatureList::OverrideState trial2_state;
} test_cases[] = {
{FeatureList::OVERRIDE_DISABLE_FEATURE,
FeatureList::OVERRIDE_DISABLE_FEATURE},
{FeatureList::OVERRIDE_DISABLE_FEATURE,
FeatureList::OVERRIDE_ENABLE_FEATURE},
{FeatureList::OVERRIDE_ENABLE_FEATURE,
FeatureList::OVERRIDE_DISABLE_FEATURE},
{FeatureList::OVERRIDE_ENABLE_FEATURE,
FeatureList::OVERRIDE_ENABLE_FEATURE},
};
FieldTrial::ActiveGroup active_group;
for (size_t i = 0; i < arraysize(test_cases); ++i) {
const auto& test_case = test_cases[i];
SCOPED_TRACE(base::StringPrintf("Test[%" PRIuS "]", i));
ClearFeatureListInstance();
FieldTrialList field_trial_list(nullptr);
std::unique_ptr<FeatureList> feature_list(new FeatureList);
FieldTrial* trial1 = FieldTrialList::CreateFieldTrial("TrialExample1", "A");
FieldTrial* trial2 = FieldTrialList::CreateFieldTrial("TrialExample2", "B");
feature_list->RegisterFieldTrialOverride(kFeatureOnByDefaultName,
test_case.trial1_state, trial1);
feature_list->RegisterFieldTrialOverride(kFeatureOffByDefaultName,
test_case.trial2_state, trial2);
RegisterFeatureListInstance(std::move(feature_list));
// Initially, neither trial should be active.
EXPECT_FALSE(FieldTrialList::IsTrialActive(trial1->trial_name()));
EXPECT_FALSE(FieldTrialList::IsTrialActive(trial2->trial_name()));
const bool expected_enabled_1 =
(test_case.trial1_state == FeatureList::OVERRIDE_ENABLE_FEATURE);
EXPECT_EQ(expected_enabled_1, FeatureList::IsEnabled(kFeatureOnByDefault));
// The above should have activated |trial1|.
EXPECT_TRUE(FieldTrialList::IsTrialActive(trial1->trial_name()));
EXPECT_FALSE(FieldTrialList::IsTrialActive(trial2->trial_name()));
const bool expected_enabled_2 =
(test_case.trial2_state == FeatureList::OVERRIDE_ENABLE_FEATURE);
EXPECT_EQ(expected_enabled_2, FeatureList::IsEnabled(kFeatureOffByDefault));
// The above should have activated |trial2|.
EXPECT_TRUE(FieldTrialList::IsTrialActive(trial1->trial_name()));
EXPECT_TRUE(FieldTrialList::IsTrialActive(trial2->trial_name()));
}
}
TEST_F(FeatureListTest, FieldTrialAssociateUseDefault) {
FieldTrialList field_trial_list(nullptr);
std::unique_ptr<FeatureList> feature_list(new FeatureList);
FieldTrial* trial1 = FieldTrialList::CreateFieldTrial("TrialExample1", "A");
FieldTrial* trial2 = FieldTrialList::CreateFieldTrial("TrialExample2", "B");
feature_list->RegisterFieldTrialOverride(
kFeatureOnByDefaultName, FeatureList::OVERRIDE_USE_DEFAULT, trial1);
feature_list->RegisterFieldTrialOverride(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_USE_DEFAULT, trial2);
RegisterFeatureListInstance(std::move(feature_list));
// Initially, neither trial should be active.
EXPECT_FALSE(FieldTrialList::IsTrialActive(trial1->trial_name()));
EXPECT_FALSE(FieldTrialList::IsTrialActive(trial2->trial_name()));
// Check the feature enabled state is its default.
EXPECT_TRUE(FeatureList::IsEnabled(kFeatureOnByDefault));
// The above should have activated |trial1|.
EXPECT_TRUE(FieldTrialList::IsTrialActive(trial1->trial_name()));
EXPECT_FALSE(FieldTrialList::IsTrialActive(trial2->trial_name()));
// Check the feature enabled state is its default.
EXPECT_FALSE(FeatureList::IsEnabled(kFeatureOffByDefault));
// The above should have activated |trial2|.
EXPECT_TRUE(FieldTrialList::IsTrialActive(trial1->trial_name()));
EXPECT_TRUE(FieldTrialList::IsTrialActive(trial2->trial_name()));
}
TEST_F(FeatureListTest, CommandLineTakesPrecedenceOverFieldTrial) {
ClearFeatureListInstance();
FieldTrialList field_trial_list(nullptr);
std::unique_ptr<FeatureList> feature_list(new FeatureList);
// The feature is explicitly enabled on the command-line.
feature_list->InitializeFromCommandLine(kFeatureOffByDefaultName, "");
// But the FieldTrial would set the feature to disabled.
FieldTrial* trial = FieldTrialList::CreateFieldTrial("TrialExample2", "A");
feature_list->RegisterFieldTrialOverride(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_DISABLE_FEATURE, trial);
RegisterFeatureListInstance(std::move(feature_list));
EXPECT_FALSE(FieldTrialList::IsTrialActive(trial->trial_name()));
// Command-line should take precedence.
EXPECT_TRUE(FeatureList::IsEnabled(kFeatureOffByDefault));
// Since the feature is on due to the command-line, and not as a result of the
// field trial, the field trial should not be activated (since the Associate*
// API wasn't used.)
EXPECT_FALSE(FieldTrialList::IsTrialActive(trial->trial_name()));
}
TEST_F(FeatureListTest, IsFeatureOverriddenFromCommandLine) {
ClearFeatureListInstance();
FieldTrialList field_trial_list(nullptr);
std::unique_ptr<FeatureList> feature_list(new FeatureList);
// No features are overridden from the command line yet
EXPECT_FALSE(feature_list->IsFeatureOverriddenFromCommandLine(
kFeatureOnByDefaultName, FeatureList::OVERRIDE_DISABLE_FEATURE));
EXPECT_FALSE(feature_list->IsFeatureOverriddenFromCommandLine(
kFeatureOnByDefaultName, FeatureList::OVERRIDE_ENABLE_FEATURE));
EXPECT_FALSE(feature_list->IsFeatureOverriddenFromCommandLine(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_DISABLE_FEATURE));
EXPECT_FALSE(feature_list->IsFeatureOverriddenFromCommandLine(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_ENABLE_FEATURE));
// Now, enable |kFeatureOffByDefaultName| via the command-line.
feature_list->InitializeFromCommandLine(kFeatureOffByDefaultName, "");
// It should now be overridden for the enabled group.
EXPECT_FALSE(feature_list->IsFeatureOverriddenFromCommandLine(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_DISABLE_FEATURE));
EXPECT_TRUE(feature_list->IsFeatureOverriddenFromCommandLine(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_ENABLE_FEATURE));
// Register a field trial to associate with the feature and ensure that the
// results are still the same.
feature_list->AssociateReportingFieldTrial(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_ENABLE_FEATURE,
FieldTrialList::CreateFieldTrial("Trial1", "A"));
EXPECT_FALSE(feature_list->IsFeatureOverriddenFromCommandLine(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_DISABLE_FEATURE));
EXPECT_TRUE(feature_list->IsFeatureOverriddenFromCommandLine(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_ENABLE_FEATURE));
// Now, register a field trial to override |kFeatureOnByDefaultName| state
// and check that the function still returns false for that feature.
feature_list->RegisterFieldTrialOverride(
kFeatureOnByDefaultName, FeatureList::OVERRIDE_DISABLE_FEATURE,
FieldTrialList::CreateFieldTrial("Trial2", "A"));
EXPECT_FALSE(feature_list->IsFeatureOverriddenFromCommandLine(
kFeatureOnByDefaultName, FeatureList::OVERRIDE_DISABLE_FEATURE));
EXPECT_FALSE(feature_list->IsFeatureOverriddenFromCommandLine(
kFeatureOnByDefaultName, FeatureList::OVERRIDE_ENABLE_FEATURE));
RegisterFeatureListInstance(std::move(feature_list));
// Check the expected feature states for good measure.
EXPECT_TRUE(FeatureList::IsEnabled(kFeatureOffByDefault));
EXPECT_FALSE(FeatureList::IsEnabled(kFeatureOnByDefault));
}
TEST_F(FeatureListTest, AssociateReportingFieldTrial) {
struct {
const char* enable_features;
const char* disable_features;
bool expected_enable_trial_created;
bool expected_disable_trial_created;
} test_cases[] = {
// If no enable/disable flags are specified, no trials should be created.
{"", "", false, false},
// Enabling the feature should result in the enable trial created.
{kFeatureOffByDefaultName, "", true, false},
// Disabling the feature should result in the disable trial created.
{"", kFeatureOffByDefaultName, false, true},
};
const char kTrialName[] = "ForcingTrial";
const char kForcedOnGroupName[] = "ForcedOn";
const char kForcedOffGroupName[] = "ForcedOff";
for (size_t i = 0; i < arraysize(test_cases); ++i) {
const auto& test_case = test_cases[i];
SCOPED_TRACE(base::StringPrintf("Test[%" PRIuS "]: [%s] [%s]", i,
test_case.enable_features,
test_case.disable_features));
ClearFeatureListInstance();
FieldTrialList field_trial_list(nullptr);
std::unique_ptr<FeatureList> feature_list(new FeatureList);
feature_list->InitializeFromCommandLine(test_case.enable_features,
test_case.disable_features);
FieldTrial* enable_trial = nullptr;
if (feature_list->IsFeatureOverriddenFromCommandLine(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_ENABLE_FEATURE)) {
enable_trial = base::FieldTrialList::CreateFieldTrial(kTrialName,
kForcedOnGroupName);
feature_list->AssociateReportingFieldTrial(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_ENABLE_FEATURE,
enable_trial);
}
FieldTrial* disable_trial = nullptr;
if (feature_list->IsFeatureOverriddenFromCommandLine(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_DISABLE_FEATURE)) {
disable_trial = base::FieldTrialList::CreateFieldTrial(
kTrialName, kForcedOffGroupName);
feature_list->AssociateReportingFieldTrial(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_DISABLE_FEATURE,
disable_trial);
}
EXPECT_EQ(test_case.expected_enable_trial_created, enable_trial != nullptr);
EXPECT_EQ(test_case.expected_disable_trial_created,
disable_trial != nullptr);
RegisterFeatureListInstance(std::move(feature_list));
EXPECT_FALSE(FieldTrialList::IsTrialActive(kTrialName));
if (disable_trial) {
EXPECT_FALSE(FeatureList::IsEnabled(kFeatureOffByDefault));
EXPECT_TRUE(FieldTrialList::IsTrialActive(kTrialName));
EXPECT_EQ(kForcedOffGroupName, disable_trial->group_name());
} else if (enable_trial) {
EXPECT_TRUE(FeatureList::IsEnabled(kFeatureOffByDefault));
EXPECT_TRUE(FieldTrialList::IsTrialActive(kTrialName));
EXPECT_EQ(kForcedOnGroupName, enable_trial->group_name());
}
}
}
TEST_F(FeatureListTest, GetFeatureOverrides) {
ClearFeatureListInstance();
FieldTrialList field_trial_list(nullptr);
std::unique_ptr<FeatureList> feature_list(new FeatureList);
feature_list->InitializeFromCommandLine("A,X", "D");
FieldTrial* trial = FieldTrialList::CreateFieldTrial("Trial", "Group");
feature_list->RegisterFieldTrialOverride(kFeatureOffByDefaultName,
FeatureList::OVERRIDE_ENABLE_FEATURE,
trial);
RegisterFeatureListInstance(std::move(feature_list));
std::string enable_features;
std::string disable_features;
FeatureList::GetInstance()->GetFeatureOverrides(&enable_features,
&disable_features);
EXPECT_EQ("A,OffByDefault<Trial,X", SortFeatureListString(enable_features));
EXPECT_EQ("D", SortFeatureListString(disable_features));
FeatureList::GetInstance()->GetCommandLineFeatureOverrides(&enable_features,
&disable_features);
EXPECT_EQ("A,X", SortFeatureListString(enable_features));
EXPECT_EQ("D", SortFeatureListString(disable_features));
}
TEST_F(FeatureListTest, GetFeatureOverrides_UseDefault) {
ClearFeatureListInstance();
FieldTrialList field_trial_list(nullptr);
std::unique_ptr<FeatureList> feature_list(new FeatureList);
feature_list->InitializeFromCommandLine("A,X", "D");
FieldTrial* trial = FieldTrialList::CreateFieldTrial("Trial", "Group");
feature_list->RegisterFieldTrialOverride(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_USE_DEFAULT, trial);
RegisterFeatureListInstance(std::move(feature_list));
std::string enable_features;
std::string disable_features;
FeatureList::GetInstance()->GetFeatureOverrides(&enable_features,
&disable_features);
EXPECT_EQ("*OffByDefault<Trial,A,X", SortFeatureListString(enable_features));
EXPECT_EQ("D", SortFeatureListString(disable_features));
}
TEST_F(FeatureListTest, GetFieldTrial) {
ClearFeatureListInstance();
FieldTrialList field_trial_list(nullptr);
FieldTrial* trial = FieldTrialList::CreateFieldTrial("Trial", "Group");
std::unique_ptr<FeatureList> feature_list(new FeatureList);
feature_list->RegisterFieldTrialOverride(
kFeatureOnByDefaultName, FeatureList::OVERRIDE_USE_DEFAULT, trial);
RegisterFeatureListInstance(std::move(feature_list));
EXPECT_EQ(trial, FeatureList::GetFieldTrial(kFeatureOnByDefault));
EXPECT_EQ(nullptr, FeatureList::GetFieldTrial(kFeatureOffByDefault));
}
TEST_F(FeatureListTest, InitializeFromCommandLine_WithFieldTrials) {
ClearFeatureListInstance();
FieldTrialList field_trial_list(nullptr);
FieldTrialList::CreateFieldTrial("Trial", "Group");
std::unique_ptr<FeatureList> feature_list(new FeatureList);
feature_list->InitializeFromCommandLine("A,OffByDefault<Trial,X", "D");
RegisterFeatureListInstance(std::move(feature_list));
EXPECT_FALSE(FieldTrialList::IsTrialActive("Trial"));
EXPECT_TRUE(FeatureList::IsEnabled(kFeatureOffByDefault));
EXPECT_TRUE(FieldTrialList::IsTrialActive("Trial"));
}
TEST_F(FeatureListTest, InitializeFromCommandLine_UseDefault) {
ClearFeatureListInstance();
FieldTrialList field_trial_list(nullptr);
FieldTrialList::CreateFieldTrial("T1", "Group");
FieldTrialList::CreateFieldTrial("T2", "Group");
std::unique_ptr<FeatureList> feature_list(new FeatureList);
feature_list->InitializeFromCommandLine(
"A,*OffByDefault<T1,*OnByDefault<T2,X", "D");
RegisterFeatureListInstance(std::move(feature_list));
EXPECT_FALSE(FieldTrialList::IsTrialActive("T1"));
EXPECT_FALSE(FeatureList::IsEnabled(kFeatureOffByDefault));
EXPECT_TRUE(FieldTrialList::IsTrialActive("T1"));
EXPECT_FALSE(FieldTrialList::IsTrialActive("T2"));
EXPECT_TRUE(FeatureList::IsEnabled(kFeatureOnByDefault));
EXPECT_TRUE(FieldTrialList::IsTrialActive("T2"));
}
TEST_F(FeatureListTest, InitializeInstance) {
ClearFeatureListInstance();
std::unique_ptr<base::FeatureList> feature_list(new base::FeatureList);
FeatureList::SetInstance(std::move(feature_list));
EXPECT_TRUE(FeatureList::IsEnabled(kFeatureOnByDefault));
EXPECT_FALSE(FeatureList::IsEnabled(kFeatureOffByDefault));
// Initialize from command line if we haven't yet.
FeatureList::InitializeInstance("", kFeatureOnByDefaultName);
EXPECT_FALSE(FeatureList::IsEnabled(kFeatureOnByDefault));
EXPECT_FALSE(FeatureList::IsEnabled(kFeatureOffByDefault));
// Do not initialize from commandline if we have already.
FeatureList::InitializeInstance(kFeatureOffByDefaultName, "");
EXPECT_FALSE(FeatureList::IsEnabled(kFeatureOnByDefault));
EXPECT_FALSE(FeatureList::IsEnabled(kFeatureOffByDefault));
}
TEST_F(FeatureListTest, UninitializedInstance_IsEnabledReturnsFalse) {
ClearFeatureListInstance();
// This test case simulates the calling pattern found in code which does not
// explicitly initialize the features list.
// All IsEnabled() calls should return the default value in this scenario.
EXPECT_EQ(nullptr, FeatureList::GetInstance());
EXPECT_TRUE(FeatureList::IsEnabled(kFeatureOnByDefault));
EXPECT_EQ(nullptr, FeatureList::GetInstance());
EXPECT_FALSE(FeatureList::IsEnabled(kFeatureOffByDefault));
}
TEST_F(FeatureListTest, StoreAndRetrieveFeaturesFromSharedMemory) {
std::unique_ptr<base::FeatureList> feature_list(new base::FeatureList);
// Create some overrides.
feature_list->RegisterOverride(kFeatureOffByDefaultName,
FeatureList::OVERRIDE_ENABLE_FEATURE, nullptr);
feature_list->RegisterOverride(
kFeatureOnByDefaultName, FeatureList::OVERRIDE_DISABLE_FEATURE, nullptr);
feature_list->FinalizeInitialization();
// Create an allocator and store the overrides.
std::unique_ptr<SharedMemory> shm(new SharedMemory());
shm->CreateAndMapAnonymous(4 << 10);
SharedPersistentMemoryAllocator allocator(std::move(shm), 1, "", false);
feature_list->AddFeaturesToAllocator(&allocator);
std::unique_ptr<base::FeatureList> feature_list2(new base::FeatureList);
// Check that the new feature list is empty.
EXPECT_FALSE(feature_list2->IsFeatureOverriddenFromCommandLine(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_ENABLE_FEATURE));
EXPECT_FALSE(feature_list2->IsFeatureOverriddenFromCommandLine(
kFeatureOnByDefaultName, FeatureList::OVERRIDE_DISABLE_FEATURE));
feature_list2->InitializeFromSharedMemory(&allocator);
// Check that the new feature list now has 2 overrides.
EXPECT_TRUE(feature_list2->IsFeatureOverriddenFromCommandLine(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_ENABLE_FEATURE));
EXPECT_TRUE(feature_list2->IsFeatureOverriddenFromCommandLine(
kFeatureOnByDefaultName, FeatureList::OVERRIDE_DISABLE_FEATURE));
}
TEST_F(FeatureListTest, StoreAndRetrieveAssociatedFeaturesFromSharedMemory) {
FieldTrialList field_trial_list(nullptr);
std::unique_ptr<base::FeatureList> feature_list(new base::FeatureList);
// Create some overrides.
FieldTrial* trial1 = FieldTrialList::CreateFieldTrial("TrialExample1", "A");
FieldTrial* trial2 = FieldTrialList::CreateFieldTrial("TrialExample2", "B");
feature_list->RegisterFieldTrialOverride(
kFeatureOnByDefaultName, FeatureList::OVERRIDE_USE_DEFAULT, trial1);
feature_list->RegisterFieldTrialOverride(
kFeatureOffByDefaultName, FeatureList::OVERRIDE_USE_DEFAULT, trial2);
feature_list->FinalizeInitialization();
// Create an allocator and store the overrides.
std::unique_ptr<SharedMemory> shm(new SharedMemory());
shm->CreateAndMapAnonymous(4 << 10);
SharedPersistentMemoryAllocator allocator(std::move(shm), 1, "", false);
feature_list->AddFeaturesToAllocator(&allocator);
std::unique_ptr<base::FeatureList> feature_list2(new base::FeatureList);
feature_list2->InitializeFromSharedMemory(&allocator);
feature_list2->FinalizeInitialization();
// Check that the field trials are still associated.
FieldTrial* associated_trial1 =
feature_list2->GetAssociatedFieldTrial(kFeatureOnByDefault);
FieldTrial* associated_trial2 =
feature_list2->GetAssociatedFieldTrial(kFeatureOffByDefault);
EXPECT_EQ(associated_trial1, trial1);
EXPECT_EQ(associated_trial2, trial2);
}
} // namespace base