[SyncFS] Add a UMA to measure RTT in registration

chrome/browser/sync_file_system/drive_backend/sync_engine.cc

 // Copyright 2013 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/sync_file_system/drive_backend/sync_engine.h"
 
 #include <vector>
 
 #include "base/bind.h"
+#include "base/metrics/histogram.h"
 #include "base/threading/sequenced_worker_pool.h"
+#include "base/time/time.h"
 #include "base/values.h"
 #include "chrome/browser/drive/drive_api_service.h"
 #include "chrome/browser/drive/drive_notification_manager.h"
 #include "chrome/browser/drive/drive_notification_manager_factory.h"
 #include "chrome/browser/drive/drive_service_interface.h"
 #include "chrome/browser/drive/drive_uploader.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/signin/profile_oauth2_token_service_factory.h"
 #include "chrome/browser/signin/signin_manager_factory.h"
@@ skipping 74 matching lines @@
   scoped_refptr<base::SequencedTaskRunner> ui_task_runner_;
   base::WeakPtr<SyncEngine> sync_engine_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkerObserver);
 };
 
 namespace {
 
 void EmptyStatusCallback(SyncStatusCode status) {}
 
+void DidRegisterOrigin(const base::TimeTicks& start_time,
+                       const SyncStatusCallback& callback,
+                       SyncStatusCode status) {
+  base::TimeDelta delta(base::TimeTicks::Now() - start_time);
+  HISTOGRAM_TIMES("SyncFileSystem.RegisterOriginTime", delta);
+  callback.Run(status);
+}
+
 }  // namespace
 
 scoped_ptr<SyncEngine> SyncEngine::CreateForBrowserContext(
     content::BrowserContext* context) {
   scoped_refptr<base::SequencedWorkerPool> worker_pool(
       content::BrowserThread::GetBlockingPool());
   scoped_refptr<base::SequencedTaskRunner> drive_task_runner(
       worker_pool->GetSequencedTaskRunnerWithShutdownBehavior(
           worker_pool->GetSequenceToken(),
           base::SequencedWorkerPool::SKIP_ON_SHUTDOWN));
@@ skipping 105 matching lines @@
 }
 
 void SyncEngine::RegisterOrigin(
     const GURL& origin, const SyncStatusCallback& callback) {
   worker_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&SyncWorker::RegisterOrigin,
                  base::Unretained(sync_worker_.get()),
                  origin,
                  RelayCallbackToCurrentThread(
-                     FROM_HERE, callback)));
+                     FROM_HERE,
+                     base::Bind(&DidRegisterOrigin,
+                                base::TimeTicks::Now(),
+                                callback))));
 }
 
 void SyncEngine::EnableOrigin(
     const GURL& origin, const SyncStatusCallback& callback) {
   worker_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&SyncWorker::EnableOrigin,
                  base::Unretained(sync_worker_.get()),
                  origin,
                  RelayCallbackToCurrentThread(
@@ skipping 281 matching lines @@
         tracker.tracker_kind() == TRACKER_KIND_APP_ROOT;
     if (is_app_enabled && !is_app_root_tracker_enabled)
       EnableOrigin(origin, base::Bind(&EmptyStatusCallback));
     else if (!is_app_enabled && is_app_root_tracker_enabled)
       DisableOrigin(origin, base::Bind(&EmptyStatusCallback));
   }
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system