[SyncFS] Use nullptr instead of NULL

chrome/browser/sync_file_system/drive_backend/sync_engine_unittest.cc

Index: chrome/browser/sync_file_system/drive_backend/sync_engine_unittest.cc
diff --git a/chrome/browser/sync_file_system/drive_backend/sync_engine_unittest.cc b/chrome/browser/sync_file_system/drive_backend/sync_engine_unittest.cc
index c680bab01d23a1ada6b853bd25003abf82f8e3f1..a8e282968a8f0462d859bd321c97b47473e72660 100644
--- a/chrome/browser/sync_file_system/drive_backend/sync_engine_unittest.cc
+++ b/chrome/browser/sync_file_system/drive_backend/sync_engine_unittest.cc
@@ -48,16 +48,16 @@ class SyncEngineTest : public testing::Test,
     sync_engine_.reset(new drive_backend::SyncEngine(
         ui_task_runner.get(),
         worker_task_runner_.get(),
-        NULL /* drive_task_runner */,
+        nullptr /* drive_task_runner */,
         profile_dir_.path(),
-        NULL /* task_logger */,
-        NULL /* notification_manager */,
-        NULL /* extension_service */,
-        NULL /* signin_manager */,
-        NULL /* token_service */,
-        NULL /* request_context */,
+        nullptr /* task_logger */,
+        nullptr /* notification_manager */,
+        nullptr /* extension_service */,
+        nullptr /* signin_manager */,
+        nullptr /* token_service */,
+        nullptr /* request_context */,
         scoped_ptr<SyncEngine::DriveServiceFactory>(),
-        NULL /* in_memory_env */));
+        nullptr /* in_memory_env */));
 
     sync_engine_->InitializeForTesting(
         fake_drive_service.Pass(),
@@ -74,8 +74,8 @@ class SyncEngineTest : public testing::Test,
     WaitForWorkerTaskRunner();
     worker_pool_->Shutdown();
 
-    worker_task_runner_ = NULL;
-    worker_pool_ = NULL;
+    worker_task_runner_ = nullptr;
+    worker_pool_ = nullptr;
 
     base::RunLoop().RunUntilIdle();
   }