If users clear history, the previews recency rule should be cleared

components/previews/core/previews_black_list_unittest.cc

Index: components/previews/core/previews_black_list_unittest.cc
diff --git a/components/previews/core/previews_black_list_unittest.cc b/components/previews/core/previews_black_list_unittest.cc
index 2c8a1fc3b80a1dddb25925352f5cf68159fa796b..09e5bdc8213d2398f30fcd90ed3da1b36ab1c4cc 100644
--- a/components/previews/core/previews_black_list_unittest.cc
+++ b/components/previews/core/previews_black_list_unittest.cc
@@ -603,4 +603,59 @@ TEST_F(PreviewsBlackListTest, AddPreviewUMA) {
                                      1);
 }
 
+TEST_F(PreviewsBlackListTest, ClearingBlackListClearsRecentNavigation) {
+  const GURL url("http://www.url.com");
+
+  const size_t host_indifferent_history = 1;
+  const int host_indifferent_threshold = host_indifferent_history + 1;
+  const int duration_in_days = 365;
+  // Disable single opt out by setting duration to 0.
+  const int single_opt_out_duration = 5;
+  base::FieldTrialList field_trial_list(nullptr);
+  std::map<std::string, std::string> params;

[bengr, 2017/05/15 21:15:14]

#include <map>

[RyanSturm, 2017/05/15 21:58:58]

Done.

+  params["per_host_black_list_duration_in_days"] =
+      base::IntToString(duration_in_days);
+  params["host_indifferent_max_stored_history_length"] =
+      base::SizeTToString(host_indifferent_history);
+  params["host_indifferent_opt_out_threshold"] =
+      base::IntToString(host_indifferent_threshold);
+  params["single_opt_out_duration_in_seconds"] =
+      base::IntToString(single_opt_out_duration);
+  ASSERT_TRUE(
+      variations::AssociateVariationParams("ClientSidePreviews", "Enabled",
+                                           params) &&
+      base::FieldTrialList::CreateFieldTrial("ClientSidePreviews", "Enabled"));
+
+  struct {
+    bool short_history_clear;
+  } tests[] = {{true}, {false}};

[bengr, 2017/05/15 21:15:14]

This is an anti-pattern. Write this as two separate tests.

[RyanSturm, 2017/05/15 21:58:59]

Done.

+
+  base::MessageLoop loop;
+  for (auto test : tests) {
+    base::SimpleTestClock* test_clock = new base::SimpleTestClock();
+    base::Time start = test_clock->Now();
+    if (!test.short_history_clear) {
+      test_clock->Advance(
+          base::TimeDelta::FromSeconds(single_opt_out_duration));
+    }
+
+    TestPreviewsOptOutStore* opt_out_store = new TestPreviewsOptOutStore();
+
+    std::unique_ptr<PreviewsBlackList> black_list(new PreviewsBlackList(
+        base::WrapUnique(opt_out_store), base::WrapUnique(test_clock)));
+
+    black_list->AddPreviewNavigation(url, true /* opt_out */,
+                                     PreviewsType::OFFLINE);
+    test_clock->Advance(base::TimeDelta::FromSeconds(1));
+    black_list->ClearBlackList(start, test_clock->Now());
+    base::RunLoop().RunUntilIdle();
+
+    EXPECT_EQ(test.short_history_clear
+                  ? PreviewsEligibilityReason::USER_RECENTLY_OPTED_OUT
+                  : PreviewsEligibilityReason::ALLOWED,
+              black_list->IsLoadedAndAllowed(url, PreviewsType::OFFLINE));
+  }
+  variations::testing::ClearAllVariationParams();
+}
+
 }  // namespace previews