Add Statistics for SupervisedUserSettingService during merging and syncing data.

chrome/browser/supervised_user/supervised_user_settings_service.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/supervised_user_settings_service.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/callback.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
+#include "base/metrics/histogram.h"
 #include "base/prefs/json_pref_store.h"
 #include "base/prefs/pref_filter.h"
 #include "base/strings/string_util.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/supervised_user/supervised_user_url_filter.h"
 #include "chrome/common/chrome_constants.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/user_metrics.h"
 #include "sync/api/sync_change.h"
 #include "sync/api/sync_error_factory.h"
@@ skipping 207 matching lines @@
 
   SyncMergeResult result(SUPERVISED_USER_SETTINGS);
   // Process all the accumulated changes from the queued items.
   if (change_list.size() > 0) {
     store_->ReportValueChanged(kQueuedItems,
                                WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
     result.set_error(
         sync_processor_->ProcessSyncChanges(FROM_HERE, change_list));
   }
 
-  // TODO(bauerb): Statistics?
+  UMA_HISTOGRAM_ENUMERATION("SupervisedUserSettingService.SyncMergeResult",
+                            result.model_type(), syncer::MODEL_TYPE_COUNT);
+
   return result;
 }
 
 void SupervisedUserSettingsService::StopSyncing(ModelType type) {
   DCHECK_EQ(syncer::SUPERVISED_USER_SETTINGS, type);
   sync_processor_.reset();
   error_handler_.reset();
 }
 
 SyncDataList SupervisedUserSettingsService::GetAllSyncData(
@@ skipping 159 matching lines @@
   return settings;
 }
 
 void SupervisedUserSettingsService::InformSubscribers() {
   if (!IsReady())
     return;
 
   scoped_ptr<base::DictionaryValue> settings = GetSettings();
   callback_list_.Notify(settings.get());
 }