[USS] Move GetAllNodes from backend to controller

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 99c74b78c856366553531f3c283eedf70a852041..ed3e29cc507e1b881fb3e335d514747f340f52ce 100644
--- a/components/sync/driver/proxy_data_type_controller.cc
+++ b/components/sync/driver/proxy_data_type_controller.cc
@@ -4,6 +4,10 @@
 
 #include "components/sync/driver/proxy_data_type_controller.h"
 
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/memory/ptr_util.h"
+#include "base/values.h"
 #include "components/sync/api/sync_merge_result.h"
 
 namespace sync_driver {
@@ -70,4 +74,8 @@ void ProxyDataTypeController::ActivateDataType(
 void ProxyDataTypeController::DeactivateDataType(
     BackendDataTypeConfigurer* configurer) {}
 
+void ProxyDataTypeController::GetAllNodes(const AllNodesCallback& callback) {
+  callback.Run(type(), base::WrapUnique(new base::ListValue()));
+}
+
 }  // namespace sync_driver