[Sync] Convert DTCs to be not RefCounted and NonThreadSafe.

components/sync/driver/proxy_data_type_controller.cc

Index: components/sync/driver/proxy_data_type_controller.cc
diff --git a/components/sync/driver/proxy_data_type_controller.cc b/components/sync/driver/proxy_data_type_controller.cc
index ed3e29cc507e1b881fb3e335d514747f340f52ce..ae2e263f84df7bc56c1d3c957ec83cc50120247d 100644
--- a/components/sync/driver/proxy_data_type_controller.cc
+++ b/components/sync/driver/proxy_data_type_controller.cc
@@ -12,13 +12,9 @@
 
 namespace sync_driver {
 
-ProxyDataTypeController::ProxyDataTypeController(
-    const scoped_refptr<base::SingleThreadTaskRunner>& ui_thread,
-    syncer::ModelType type)
-    : DataTypeController(ui_thread, base::Closure()),
-      state_(NOT_RUNNING),
-      type_(type) {
-  DCHECK(syncer::ProxyTypes().Has(type_));
+ProxyDataTypeController::ProxyDataTypeController(syncer::ModelType type)
+    : DataTypeController(type, base::Closure()), state_(NOT_RUNNING) {
+  DCHECK(syncer::ProxyTypes().Has(type));
 }
 
 ProxyDataTypeController::~ProxyDataTypeController() {}
@@ -29,6 +25,7 @@ bool ProxyDataTypeController::ShouldLoadModelBeforeConfigure() const {
 
 void ProxyDataTypeController::LoadModels(
     const ModelLoadCallback& model_load_callback) {
+  DCHECK(CalledOnValidThread());
   state_ = MODEL_LOADED;
   model_load_callback.Run(type(), syncer::SyncError());
 }
@@ -38,8 +35,9 @@ void ProxyDataTypeController::RegisterWithBackend(
 
 void ProxyDataTypeController::StartAssociating(
     const StartCallback& start_callback) {
-  syncer::SyncMergeResult local_merge_result(type_);
-  syncer::SyncMergeResult syncer_merge_result(type_);
+  DCHECK(CalledOnValidThread());
+  syncer::SyncMergeResult local_merge_result(type());
+  syncer::SyncMergeResult syncer_merge_result(type());
   state_ = RUNNING;
   start_callback.Run(DataTypeController::OK, local_merge_result,
                      syncer_merge_result);
@@ -49,11 +47,6 @@ void ProxyDataTypeController::Stop() {
   state_ = NOT_RUNNING;
 }
 
-syncer::ModelType ProxyDataTypeController::type() const {
-  DCHECK(syncer::ProxyTypes().Has(type_));
-  return type_;
-}
-
 std::string ProxyDataTypeController::name() const {
   // For logging only.
   return syncer::ModelTypeToString(type());
@@ -63,11 +56,6 @@ DataTypeController::State ProxyDataTypeController::state() const {
   return state_;
 }
 
-void ProxyDataTypeController::OnSingleDataTypeUnrecoverableError(
-    const syncer::SyncError& error) {
-  NOTIMPLEMENTED();
-}
-
 void ProxyDataTypeController::ActivateDataType(
     BackendDataTypeConfigurer* configurer) {}
 
@@ -78,4 +66,10 @@ void ProxyDataTypeController::GetAllNodes(const AllNodesCallback& callback) {
   callback.Run(type(), base::WrapUnique(new base::ListValue()));
 }
 
+std::unique_ptr<syncer::DataTypeErrorHandler>
+ProxyDataTypeController::CreateErrorHandler() {
+  NOTREACHED();
+  return nullptr;
+}
+
 }  // namespace sync_driver