Add migration from old to new NTP Promo pref structure.

ios/chrome/browser/notification_promo_unittest.cc

Index: ios/chrome/browser/notification_promo_unittest.cc
diff --git a/ios/chrome/browser/notification_promo_unittest.cc b/ios/chrome/browser/notification_promo_unittest.cc
index 642836a3d3478d7e1e1bd10159b019e49fc5d491..f2697966142c6a9f03009d2aab6ec658589797ed 100644
--- a/ios/chrome/browser/notification_promo_unittest.cc
+++ b/ios/chrome/browser/notification_promo_unittest.cc
@@ -288,6 +288,54 @@ class NotificationPromoTest : public testing::Test {
     notification_promo_.WritePrefs();
   }
 
+  // Tests that if data is saved in the old pref structure, it is successfully
+  // migrated to the new structure that supports saving multiple promos.
+  // TODO(crbug.com/623726) Remove this method when migration is no longer
+  // needed as most users have been upgraded to the new pref structure.
+  void TestMigrationOfOldPrefs() {
+    NotificationPromo promo(&local_state_);
+    promo.InitFromVariations();
+
+    // Pick values for each variable that is saved into old prefs structure.
+    double first_view_time = 2.0;
+    int views = max_views_ + 1;
+    bool closed = true;
+
+    // Save data into old prefs structure.
+    base::DictionaryValue* ntp_promo = new base::DictionaryValue;
+    ntp_promo->SetInteger("id", promo.promo_id_);
+    ntp_promo->SetDouble("first_view_time", first_view_time);
+    ntp_promo->SetInteger("views", views);
+    ntp_promo->SetBoolean("closed", true);
+
+    base::ListValue* promo_list = new base::ListValue;
+    promo_list->Set(0, ntp_promo);
+
+    std::string promo_list_key = "mobile_ntp_whats_new_promo";
+    std::string promo_dict_key = "ios.ntppromo";
+
+    base::DictionaryValue promo_dict;
+    promo_dict.Set(promo_list_key, promo_list);
+    local_state_.Set(promo_dict_key, promo_dict);
+
+    // Initialize promo and verify that its instance variables match the data
+    // saved in the old structure.
+    promo.InitFromPrefs(promo_type_);
+    EXPECT_EQ(first_view_time, promo.first_view_time_);
+    EXPECT_EQ(views, promo.views_);
+    EXPECT_EQ(closed, promo.closed_);
+    EXPECT_FALSE(promo.CanShow());
+
+    // Verify that old pref structure was cleared.
+    const base::DictionaryValue* current_promo_dict =
+        local_state_.GetDictionary(promo_dict_key);
+    // Do not continue further if no dictionary was found at the key in prefs.
+    ASSERT_TRUE(current_promo_dict);
+    const base::ListValue* current_promo_list = NULL;
+    current_promo_dict->GetList(promo_list_key, &current_promo_list);
+    EXPECT_FALSE(current_promo_list);
+  }
+
   const NotificationPromo& promo() const { return notification_promo_; }
 
  protected:
@@ -375,4 +423,28 @@ TEST_F(NotificationPromoTest, NotificationPromoFinchTest) {
   TestFirstViewTimeRecorded();
 }
 
+// TODO(crbug.com/623726) Remove this test case when migration is no longer
+// needed as most users have been upgraded to the new pref structure.
+TEST_F(NotificationPromoTest, NotificationPromoPrefMigrationTest) {
+  Init(
+      "{"
+      "  \"start\":\"3 Aug 1999 9:26:06 GMT\","
+      "  \"end\":\"$1\","
+      "  \"promo_text\":\"What do you think of Chrome?\","
+      "  \"payload\":"
+      "    {"
+      "      \"days_active\":7,"
+      "      \"install_age_days\":21"
+      "    },"
+      "  \"max_views\":30,"
+      "  \"max_seconds\":30,"
+      "  \"promo_id\":0"
+      "}",
+      "What do you think of Chrome?",
+      933672366,  // unix epoch for 3 Aug 1999 9:26:06 GMT.
+      0, 30, 30);
+  InitPromoFromVariations();
+  TestMigrationOfOldPrefs();
+}
+
 }  // namespace ios