move V2 classes in chrome/engine to syncer_v2 namespace

sync/internal_api/test/null_sync_context_proxy.cc

Index: sync/internal_api/test/null_sync_context_proxy.cc
diff --git a/sync/internal_api/test/null_sync_context_proxy.cc b/sync/internal_api/test/null_sync_context_proxy.cc
index 5c272e54c7fa0f891f911972b6ce3a90216f7517..cdd740fedd8269a87cd64f70edc2d11494f470eb 100644
--- a/sync/internal_api/test/null_sync_context_proxy.cc
+++ b/sync/internal_api/test/null_sync_context_proxy.cc
@@ -16,7 +16,7 @@ void NullSyncContextProxy::ConnectTypeToSync(
     syncer::ModelType type,
     const DataTypeState& data_type_state,
     const UpdateResponseDataList& saved_pending_updates,
-    const base::WeakPtr<syncer::ModelTypeSyncProxyImpl>& type_sync_proxy) {
+    const base::WeakPtr<ModelTypeSyncProxyImpl>& type_sync_proxy) {
   NOTREACHED() << "NullSyncContextProxy is not meant to be used";
 }