[SyncFS] Construct and destruct sync_worker in worker_task_runner

chrome/browser/sync_file_system/drive_backend/sync_engine.cc

Index: chrome/browser/sync_file_system/drive_backend/sync_engine.cc
diff --git a/chrome/browser/sync_file_system/drive_backend/sync_engine.cc b/chrome/browser/sync_file_system/drive_backend/sync_engine.cc
index be3a51a18477c1f3ae973dd9d3b7ed15d643fffe..08692c4159c7bf8ec1ca2773e06203a2c110233a 100644
--- a/chrome/browser/sync_file_system/drive_backend/sync_engine.cc
+++ b/chrome/browser/sync_file_system/drive_backend/sync_engine.cc
@@ -205,7 +205,8 @@ SyncEngine::~SyncEngine() {
   if (notification_manager_)
     notification_manager_->RemoveObserver(this);
 
-  // TODO(tzik): Destroy |sync_worker_| and |worker_observer_| on the worker.
+  worker_task_runner_->DeleteSoon(FROM_HERE, worker_observer_.release());
+  worker_task_runner_->DeleteSoon(FROM_HERE, sync_worker_.release());
 }
 
 void SyncEngine::Initialize(const base::FilePath& base_dir,
@@ -239,7 +240,6 @@ void SyncEngine::Initialize(const base::FilePath& base_dir,
   if (extension_service_)
     extension_service_weak_ptr = extension_service_->AsWeakPtr();
 
-  // TODO(peria): Use PostTask on |worker_task_runner_| to call this function.
   sync_worker_ = SyncWorker::CreateOnWorker(

[nhiroki, 2014/05/26 08:06:03]

How about renaming this or calling the ctor directly?

[peria, 2014/05/26 08:14:41]

Done.

       base_dir,
       worker_observer_.get(),
@@ -251,6 +251,11 @@ void SyncEngine::Initialize(const base::FilePath& base_dir,
     notification_manager_->AddObserver(this);
   GetDriveService()->AddObserver(this);
   net::NetworkChangeNotifier::AddNetworkChangeObserver(this);
+
+  worker_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&SyncWorker::Initialize,
+                 base::Unretained(sync_worker_.get())));

[nhiroki, 2014/05/26 08:06:03]

You may want to move this to line 249 for readability.

[peria, 2014/05/26 08:14:41]

Done.

 }
 
 void SyncEngine::AddServiceObserver(SyncServiceObserver* observer) {