Fix assist_ranker unittests

ScopedFeatureList must be initialized before testing any feature.
https://cs.chromium.org/chromium/src/base/test/scoped_feature_list.h?l=26

If it is not initialized, any feature is tested in the global
FeatureList, which could lead to bad interaction between tests.

Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: Ic2bfba36312cbebb5c0abadaf1074f7eaff37d9a
Reviewed-on: https://chromium-review.googlesource.com/1126102Reviewed-by: Roger McFarlane <rogerm@chromium.org>
Commit-Queue: Olivier Robin <olivierrobin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572604}

components/assist_ranker/base_predictor_unittest.cc

@@ -100,8 +100,8 @@ std::unique_ptr<FakePredictor> FakePredictor::Create() {
 class BasePredictorTest : public ::testing::Test {
  protected:
   BasePredictorTest() = default;
-  // Disables Query for the test predictor.
-  void DisableQuery();
+
+  void SetUp() override;
 
   ukm::SourceId GetSourceId();
 
@@ -120,16 +120,17 @@ class BasePredictorTest : public ::testing::Test {
   DISALLOW_COPY_AND_ASSIGN(BasePredictorTest);
 };
 
+void BasePredictorTest::SetUp() {
+  ::testing::Test::SetUp();
+  scoped_feature_list_.Init();
+}
+
 ukm::SourceId BasePredictorTest::GetSourceId() {
   ukm::SourceId source_id = ukm::UkmRecorder::GetNewSourceID();
   test_ukm_recorder_.UpdateSourceURL(source_id, GURL(kTestNavigationUrl));
   return source_id;
 }
 
-void BasePredictorTest::DisableQuery() {
-  scoped_feature_list_.InitWithFeatures({}, {kTestRankerQuery});
-}
-
 TEST_F(BasePredictorTest, BaseTest) {
   auto predictor = FakePredictor::Create();
   EXPECT_EQ(kTestModelName, predictor->GetModelName());
@@ -139,7 +140,8 @@ TEST_F(BasePredictorTest, BaseTest) {
 }
 
 TEST_F(BasePredictorTest, QueryDisabled) {
-  DisableQuery();
+  base::test::ScopedFeatureList scoped_feature_list;
+  scoped_feature_list.InitAndDisableFeature(kTestRankerQuery);
   auto predictor = FakePredictor::Create();
   EXPECT_EQ(kTestModelName, predictor->GetModelName());
   EXPECT_EQ(kTestDefaultModelUrl, predictor->GetModelUrl());

components/assist_ranker/binary_classifier_predictor_unittest.cc

@@ -9,6 +9,7 @@
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/feature_list.h"
+#include "base/test/scoped_feature_list.h"
 #include "components/assist_ranker/fake_ranker_model_loader.h"
 #include "components/assist_ranker/proto/ranker_model.pb.h"
 #include "components/assist_ranker/ranker_model.h"
@@ -20,6 +21,8 @@ using ::assist_ranker::testing::FakeRankerModelLoader;
 
 class BinaryClassifierPredictorTest : public ::testing::Test {
  public:
+  void SetUp() override;
+
   std::unique_ptr<BinaryClassifierPredictor> InitPredictor(
       std::unique_ptr<RankerModel> ranker_model,
       const PredictorConfig& config);
@@ -33,8 +36,14 @@ class BinaryClassifierPredictorTest : public ::testing::Test {
   const std::string feature_ = "feature";
   const float weight_ = 1.0;
   const float threshold_ = 0.5;
+  base::test::ScopedFeatureList scoped_feature_list_;
 };
 
+void BinaryClassifierPredictorTest::SetUp() {
+  ::testing::Test::SetUp();
+  scoped_feature_list_.Init();
+}
+
 std::unique_ptr<BinaryClassifierPredictor>
 BinaryClassifierPredictorTest::InitPredictor(
     std::unique_ptr<RankerModel> ranker_model,