Add Statistics for SupervisedUserSettingService during merging and syncing data.

chrome/browser/supervised_user/legacy/supervised_user_shared_settings_service_unittest.cc

 // Copyright 2014 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/supervised_user/legacy/supervised_user_shared_settings_service.h"
 
 #include <string>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 69 matching lines @@
 
 class SupervisedUserSharedSettingsServiceTest : public ::testing::Test {
  protected:
   typedef base::CallbackList<void(const std::string&, const std::string&)>
       CallbackList;
 
   SupervisedUserSharedSettingsServiceTest()
       : settings_service_(profile_.GetPrefs()) {}
   ~SupervisedUserSharedSettingsServiceTest() override {}
 
-  void StartSyncing(const syncer::SyncDataList& initial_sync_data) {
+  SyncMergeResult StartSyncing(const syncer::SyncDataList& initial_sync_data) {
     sync_processor_.reset(new syncer::FakeSyncChangeProcessor);
     scoped_ptr<syncer::SyncErrorFactory> error_handler(
         new MockSyncErrorFactory(SUPERVISED_USER_SHARED_SETTINGS));
     SyncMergeResult result = settings_service_.MergeDataAndStartSyncing(
         SUPERVISED_USER_SHARED_SETTINGS, initial_sync_data,
         scoped_ptr<SyncChangeProcessor>(
             new SyncChangeProcessorWrapperForTest(sync_processor_.get())),
         std::move(error_handler));
     EXPECT_FALSE(result.error().IsSet());
+    return result;
   }
 
   const base::DictionaryValue* GetAllSettings() {
     return profile_.GetPrefs()->GetDictionary(
         prefs::kSupervisedUserSharedSettings);
   }
 
   void VerifySyncChangesAndClear() {
     SyncChangeList& changes = sync_processor_->changes();
     for (const SyncChange& sync_change : changes) {
@@ skipping 73 matching lines @@
   EXPECT_EQ(ToJson(&name), ToJson(settings_service_.GetValue(kIdA, "name")));
   EXPECT_EQ(ToJson(&age), ToJson(settings_service_.GetValue(kIdA, "age")));
   EXPECT_EQ(ToJson(&bar), ToJson(settings_service_.GetValue(kIdB, "foo")));
   EXPECT_FALSE(settings_service_.GetValue(kIdA, "foo"));
   EXPECT_FALSE(settings_service_.GetValue(kIdB, "name"));
   EXPECT_FALSE(settings_service_.GetValue(kIdC, "name"));
 }
 
 TEST_F(SupervisedUserSharedSettingsServiceTest, Merge) {
   // Set initial values, then stop syncing so we can restart.
-  StartSyncing(SyncDataList());
+  SyncMergeResult result = StartSyncing(SyncDataList());
+  EXPECT_EQ(0, result.num_items_added());
+  EXPECT_EQ(0, result.num_items_deleted());
+  EXPECT_EQ(0, result.num_items_modified());
+  EXPECT_EQ(0, result.num_items_before_association());
+  EXPECT_EQ(0, result.num_items_after_association());
 
   const char kIdA[] = "aaaaaa";
   const char kIdB[] = "bbbbbb";
   const char kIdC[] = "cccccc";
 
   FundamentalValue age(8);
   StringValue bar("bar");
   settings_service_.SetValue(kIdA, "name", StringValue("Jack"));
   settings_service_.SetValue(kIdA, "age", age);
   settings_service_.SetValue(kIdB, "foo", bar);
 
   settings_service_.StopSyncing(SUPERVISED_USER_SHARED_SETTINGS);
 
   StringValue name("Jill");
   StringValue blurp("blurp");
   SyncDataList sync_data;
   sync_data.push_back(
       SupervisedUserSharedSettingsService::CreateSyncDataForSetting(
           kIdA, "name", name, true));
   sync_data.push_back(
       SupervisedUserSharedSettingsService::CreateSyncDataForSetting(
           kIdC, "baz", blurp, true));
 
-  StartSyncing(sync_data);
+  result = StartSyncing(sync_data);
+
+  EXPECT_EQ(1, result.num_items_added());
+  EXPECT_EQ(0, result.num_items_deleted());
+  EXPECT_EQ(1, result.num_items_modified());
+  EXPECT_EQ(3, result.num_items_before_association());
+  EXPECT_EQ(4, result.num_items_after_association());
+
   EXPECT_EQ(2u, sync_processor_->changes().size());
   VerifySyncChangesAndClear();
   EXPECT_EQ(2u, changed_settings_.size());
 
   EXPECT_EQ(
       4u,
       settings_service_.GetAllSyncData(SUPERVISED_USER_SHARED_SETTINGS).size());
   EXPECT_EQ(ToJson(&name),
             ToJson(settings_service_.GetValue(kIdA, "name")));
   EXPECT_EQ(ToJson(&age), ToJson(settings_service_.GetValue(kIdA, "age")));
@@ skipping 39 matching lines @@
       settings_service_.GetAllSyncData(SUPERVISED_USER_SHARED_SETTINGS).size());
   EXPECT_EQ(ToJson(&name),
             ToJson(settings_service_.GetValue(kIdA, "name")));
   EXPECT_EQ(ToJson(&age), ToJson(settings_service_.GetValue(kIdA, "age")));
   EXPECT_EQ(ToJson(&bar), ToJson(settings_service_.GetValue(kIdB, "foo")));
   EXPECT_EQ(ToJson(&blurp), ToJson(settings_service_.GetValue(kIdC, "baz")));
   EXPECT_FALSE(settings_service_.GetValue(kIdA, "foo"));
   EXPECT_FALSE(settings_service_.GetValue(kIdB, "name"));
   EXPECT_FALSE(settings_service_.GetValue(kIdC, "name"));
 }