Block explore_sites/most_visited_client from returning when the feature is off

Change-Id: Id3998f7ae6dd0de5449a184481afd392e549b889
Bug: 1042531
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2003070
Commit-Queue: Cathy Li <chili@chromium.org>
Reviewed-by: Justin DeWitt <dewittj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732586}

chrome/browser/android/explore_sites/most_visited_client.cc

@@ -4,8 +4,9 @@
 
 #include "chrome/browser/android/explore_sites/most_visited_client.h"
 
+#include "base/feature_list.h"
 #include "base/memory/ptr_util.h"
-#include "chrome/browser/android/explore_sites/explore_sites_feature.h"
+#include "chrome/browser/android/chrome_feature_list.h"
 #include "chrome/common/webui_url_constants.h"
 #include "chrome/grit/generated_resources.h"
 #include "ui/base/l10n/l10n_util.h"
@@ -13,6 +14,9 @@
 namespace explore_sites {
 
 std::unique_ptr<MostVisitedClient> MostVisitedClient::Create() {
+  if (!base::FeatureList::IsEnabled(chrome::android::kExploreSites))
+    return nullptr;
+
   // note: wrap_unique is used because the constructor is private.
   return base::WrapUnique(new MostVisitedClient());
 }

chrome/browser/android/explore_sites/most_visited_client_unittest.cc

+// Copyright 2020 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 "chrome/browser/android/explore_sites/most_visited_client.h"
+
+#include "base/test/scoped_feature_list.h"
+#include "chrome/browser/android/chrome_feature_list.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace explore_sites {
+
+TEST(MostVisitedClientTest, ReturnsNullWhenExploreSitesDisabled) {
+  base::test::ScopedFeatureList scoped_feature_list;
+  scoped_feature_list.InitAndDisableFeature(chrome::android::kExploreSites);
+  EXPECT_EQ(nullptr, MostVisitedClient::Create());
+}
+
+TEST(MostVisitedClientTest, ReturnsNonNullWhenExploreSitesEnabled) {
+  base::test::ScopedFeatureList scoped_feature_list;
+  scoped_feature_list.InitAndEnableFeature(chrome::android::kExploreSites);
+  EXPECT_NE(nullptr, MostVisitedClient::Create());
+}
+
+}  // namespace explore_sites

chrome/test/BUILD.gn

@@ -2976,6 +2976,7 @@ test("unit_tests") {
     "../browser/android/explore_sites/image_helper_unittest.cc",
     "../browser/android/explore_sites/import_catalog_task_unittest.cc",
     "../browser/android/explore_sites/increment_shown_count_task_unittest.cc",
+    "../browser/android/explore_sites/most_visited_client_unittest.cc",
     "../browser/android/explore_sites/ntp_json_fetcher_unittest.cc",
     "../browser/android/explore_sites/record_site_click_task_unittest.cc",
     "../browser/android/history_report/data_observer_unittest.cc",