Add unit test for descriptive pending status feature flag

Bug: 824602
Change-Id: I1aa2c7c43ec1e6afc343a239c30846258a231644
Reviewed-on: https://chromium-review.googlesource.com/978545
Commit-Queue: Candice Sy <cmsy@google.com>
Reviewed-by: Cathy Li <chili@chromium.org>
Cr-Commit-Position: refs/heads/master@{#545652}

components/offline_pages/core/offline_page_feature_unittest.cc

@@ -124,4 +124,15 @@ TEST(OfflinePageFeatureTest, OfflinePagesInDownloadHomeOpenInCct) {
   EXPECT_TRUE(offline_pages::ShouldOfflinePagesInDownloadHomeOpenInCct());
 }
 
+TEST(OfflinePageFeatureTest, OfflinePagesDescriptivePendingStatus) {
+  // Disabled by default.
+  EXPECT_FALSE(offline_pages::IsOfflinePagesDescriptivePendingStatusEnabled());
+
+  // Check if helper method works correctly when the features is enabled.
+  base::test::ScopedFeatureList scoped_feature_list;
+  scoped_feature_list.InitAndEnableFeature(
+      kOfflinePagesDescriptivePendingStatusFeature);
+  EXPECT_TRUE(offline_pages::IsOfflinePagesDescriptivePendingStatusEnabled());
+}
+
 }  // namespace offline_pages