[USS] Change the place where SharedModelTypeProcessor got created

components/sync_driver/non_blocking_data_type_controller.cc

Index: components/sync_driver/non_blocking_data_type_controller.cc
diff --git a/components/sync_driver/non_blocking_data_type_controller.cc b/components/sync_driver/non_blocking_data_type_controller.cc
index f2996ab1e97325dfd0b5577de28efb704b36a651..9da6850fea30d3f4b5da435f41ff12fcbcf9a9e3 100644
--- a/components/sync_driver/non_blocking_data_type_controller.cc
+++ b/components/sync_driver/non_blocking_data_type_controller.cc
@@ -55,7 +55,7 @@ void NonBlockingDataTypeController::LoadModels(
           FROM_HERE,
           base::Bind(
               &syncer_v2::SharedModelTypeProcessor::OnSyncStarting,
-              type_processor(),
+              base::Unretained(type_processor()),

[skym, 2016/03/04 22:12:28]

Danger!

[Gang Wu, 2016/03/08 20:35:25]

Done.

               base::Bind(&NonBlockingDataTypeController::OnProcessorStarted,
                          this)))) {
     LoadModelsDone(
@@ -151,7 +151,7 @@ void NonBlockingDataTypeController::Stop() {
   RunOnModelThread(
       FROM_HERE,
       base::Bind(&syncer_v2::SharedModelTypeProcessor::DisconnectSync,
-                 type_processor()));
+                 base::Unretained(type_processor())));

[skym, 2016/03/04 22:12:28]

I think it's important we have a weak ptr to verify things are still alive.

[Gang Wu, 2016/03/08 20:35:25]

Done.

 }
 
 std::string NonBlockingDataTypeController::name() const {
@@ -213,9 +213,16 @@ void NonBlockingDataTypeController::RecordUnrecoverableError() {
                             syncer::MODEL_TYPE_COUNT);
 }
 
-base::WeakPtr<syncer_v2::SharedModelTypeProcessor>
+syncer_v2::SharedModelTypeProcessor*
 NonBlockingDataTypeController::type_processor() const {
-  return type_processor_;
+  base::WeakPtr<syncer_v2::ModelTypeService> model_type_service =
+      sync_client_->GetModelTypeServiceForType(type());
+  if (!model_type_service.get()) {

[skym, 2016/03/04 22:12:28]

This is only safe on the model thread.

[Gang Wu, 2016/03/08 20:35:25]

Done.

+    return NULL;
+  }
+
+  return static_cast<syncer_v2::SharedModelTypeProcessor*>(
+      model_type_service->change_processor());
 }
 
 syncer::ModelType NonBlockingDataTypeController::type() const {
@@ -231,13 +238,7 @@ void NonBlockingDataTypeController::InitializeProcessorOnModelThread() {
     // TODO(gangwu): Add SyncError and then call start_callback with it. also
     // set an error state to |state_|.
   }
-
-  scoped_ptr<syncer_v2::SharedModelTypeProcessor> shared_model_type_processor(
-      make_scoped_ptr(new syncer_v2::SharedModelTypeProcessor(
-          type(), model_type_service.get())));
-  type_processor_ = shared_model_type_processor->AsWeakPtrForUI();
-  model_type_service->set_change_processor(
-      std::move(shared_model_type_processor));
+  model_type_service->InitializeProcessor(type());
 }
 
 void NonBlockingDataTypeController::InitializeProcessor() {