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..1e2c690aa7328ac59a480973922b6c113b043178 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
@@ -201,6 +201,14 @@ SupervisedUserSharedSettingsService::MergeDataAndStartSyncing(
   // We keep a map from MU ID to the set of keys that we have seen in the
   // initial sync data.
   std::map<std::string, std::set<std::string> > seen_keys;
+  SyncMergeResult result(SUPERVISED_USER_SHARED_SETTINGS);
+  int num_added = 0;
+  int num_modified = 0;
+
+  DictionaryPrefUpdate update_prefs(prefs_,

[Bernhard Bauer, 2016/01/06 16:41:50]

If you don't need to modify anything, you can just use prefs_->GetDictionary().

[Deepak, 2016/01/07 09:52:31]

Done.

+                                    prefs::kSupervisedUserSharedSettings);
+  base::DictionaryValue* pref_dict = update_prefs.Get();
+  result.set_num_items_before_association(pref_dict->size());

[Bernhard Bauer, 2016/01/06 16:41:50]

Can you put this into a local variable like |num_added| and |num_modified|, then
construct the result below like you did previously?

Also, isn't this a two-level dictionary, so we'd need to iterate over it and add
the sizes of its child dictionaries?

[Deepak, 2016/01/07 09:52:31]

Done.

 
   // Iterate over all initial sync data, and update it locally. This means that
   // the value from the server always wins over a local value.
@@ -224,6 +232,10 @@ SupervisedUserSharedSettingsService::MergeDataAndStartSyncing(
         kAcknowledged, supervised_user_shared_setting.acknowledged());
     callbacks_.Notify(su_id, key);
 
+    if (seen_keys.find(su_id) == seen_keys.end())
+      num_added++;
+    else
+      num_modified++;
     seen_keys[su_id].insert(key);
   }
 
@@ -252,14 +264,16 @@ SupervisedUserSharedSettingsService::MergeDataAndStartSyncing(
     }
   }
 
-  SyncMergeResult result(SUPERVISED_USER_SHARED_SETTINGS);
   // Process all the accumulated changes.
   if (change_list.size() > 0) {
     result.set_error(
         sync_processor_->ProcessSyncChanges(FROM_HERE, change_list));
   }
 
-  // TODO(bauerb): Statistics?
+  result.set_num_items_added(num_added);
+  result.set_num_items_modified(num_modified);
+  result.set_num_items_deleted(0);

[Bernhard Bauer, 2016/01/06 16:41:50]

It's fine not to set this value (0 is the default anyway), I just wanted you to
verify it.

[Deepak, 2016/01/07 09:52:31]

Done.

+  result.set_num_items_after_association(pref_dict->size());
   return result;
 }