Add migration from old to new NTP Promo pref structure.

ios/chrome/browser/notification_promo_unittest.cc

 // Copyright (c) 2016 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 <stddef.h>
 
 #include <memory>
 #include <vector>
 
 #include "base/json/json_reader.h"
@@ skipping 270 matching lines @@
     temp_promo.InitFromVariations();
     temp_promo.InitFromPrefs(promo_type_);
 
     EXPECT_EQ(first_viewed, temp_promo.first_view_time_);
 
     notification_promo_.views_ = 0;
     notification_promo_.first_view_time_ = 0;
     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.
+  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);
+
+    base::DictionaryValue promo_dict;
+    promo_dict.Set("mobile_ntp_whats_new_promo", promo_list);
+    local_state_.Set("ios.ntppromo", promo_dict);
+
+    // Initialize promo and verify that its instance variables match the data

[rohitrao (ping after 24h), 2016/06/27 17:04:19]

Also verify that the old prefs are gone?

[gchatz, 2016/06/27 23:12:22]

Added check for this.

+    // 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());
+  }
+
   const NotificationPromo& promo() const { return notification_promo_; }
 
  protected:
   TestingPrefServiceSimple local_state_;
 
  private:
   NotificationPromo notification_promo_;
   std::unique_ptr<base::FieldTrialList> field_trial_list_;
   bool received_notification_;
   std::unique_ptr<base::DictionaryValue> test_json_;
@@ skipping 67 matching lines @@
   // Test various conditions of CanShow.
   TestViews();
   TestClosed();
   TestPromoText();
   TestTime();
   TestMaxTime();
 
   TestFirstViewTimeRecorded();
 }
 
+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