Add Statistics for SupervisedUserSettingService during merging and syncing data.

chrome/browser/supervised_user/legacy/supervised_user_shared_settings_service.cc

Index: chrome/browser/supervised_user/legacy/supervised_user_shared_settings_service.cc
diff --git a/chrome/browser/supervised_user/legacy/supervised_user_shared_settings_service.cc b/chrome/browser/supervised_user/legacy/supervised_user_shared_settings_service.cc
index 60ec741691a6160e6fb02412b393bfb035aeac18..ee03b9b76d9f15aa269151159bd70841c3c7ba5b 100644
--- a/chrome/browser/supervised_user/legacy/supervised_user_shared_settings_service.cc
+++ b/chrome/browser/supervised_user/legacy/supervised_user_shared_settings_service.cc
@@ -232,12 +232,14 @@ SupervisedUserSharedSettingsService::MergeDataAndStartSyncing(
   SyncChangeList change_list;
   const DictionaryValue* all_settings =
       prefs_->GetDictionary(prefs::kSupervisedUserSharedSettings);
+  int num_association = 0;
   for (DictionaryValue::Iterator it(*all_settings); !it.IsAtEnd();
        it.Advance()) {
     const DictionaryValue* dict = NULL;
     bool success = it.value().GetAsDictionary(&dict);
     DCHECK(success);
 
+    num_association += dict->size();
     const std::set<std::string>& seen = seen_keys[it.key()];
     for (DictionaryValue::Iterator jt(*dict); !jt.IsAtEnd(); jt.Advance()) {
       // We only need to upload settings that we haven't seen in the initial
@@ -259,7 +261,9 @@ SupervisedUserSharedSettingsService::MergeDataAndStartSyncing(
         sync_processor_->ProcessSyncChanges(FROM_HERE, change_list));
   }
 
-  // TODO(bauerb): Statistics?
+  result.set_num_items_added(change_list.size());

[Bernhard Bauer, 2016/01/05 09:37:30]

Wait, is this right? IIUC, num_items_added is the number of items added to the
_local_ set of data, whereas this is the number of items added remotely.

[Deepak, 2016/01/05 13:29:19]

Done.

+  result.set_num_items_before_association(num_association - change_list.size());
+  result.set_num_items_after_association(num_association);
   return result;
 }