Sync: Don't set/use Parent ID for non-hierarchical sync data types.

components/sync_driver/generic_change_processor.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/sync_driver/generic_change_processor.h"
 
 #include "base/location.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/thread_task_runner_handle.h"
@@ skipping 476 matching lines @@
 // the compiler attempts to merge it with other calls, losing useful information
 // in breakpad uploads.
 syncer::SyncError GenericChangeProcessor::HandleActionAdd(
     const syncer::SyncChange& change,
     const std::string& type_str,
     const syncer::WriteTransaction& trans,
     syncer::WriteNode* sync_node,
     syncer::AttachmentIdSet* new_attachments) {
   // TODO(sync): Handle other types of creation (custom parents, folders,
   // etc.).
-  syncer::ReadNode root_node(&trans);
   const syncer::SyncDataLocal sync_data_local(change.sync_data());
-  if (root_node.InitTypeRoot(sync_data_local.GetDataType()) !=
-      syncer::BaseNode::INIT_OK) {
-    syncer::SyncError error(FROM_HERE,
-                            syncer::SyncError::DATATYPE_ERROR,
-                            "Failed to look up root node for type " + type_str,
-                            type_);
-    error_handler()->OnSingleDataTypeUnrecoverableError(error);
-    NOTREACHED();
-    LOG(ERROR) << "Create: no root node.";
-    return error;
-  }
   syncer::WriteNode::InitUniqueByCreationResult result =
-      sync_node->InitUniqueByCreation(
-          sync_data_local.GetDataType(), root_node, sync_data_local.GetTag());
+      sync_node->InitUniqueByCreation(sync_data_local.GetDataType(),
+                                      sync_data_local.GetTag());
   if (result != syncer::WriteNode::INIT_SUCCESS) {
     std::string error_prefix = "Failed to create " + type_str + " node: " +
                                change.location().ToString() + ", ";
     switch (result) {
       case syncer::WriteNode::INIT_FAILED_EMPTY_TAG: {
         syncer::SyncError error;
         error.Reset(FROM_HERE, error_prefix + "empty tag", type_);
         error_handler()->OnSingleDataTypeUnrecoverableError(error);
         LOG(ERROR) << "Create: Empty tag.";
         return error;
@@ skipping 188 matching lines @@
   }
 }
 
 scoped_ptr<syncer::AttachmentService>
 GenericChangeProcessor::GetAttachmentService() const {
   return scoped_ptr<syncer::AttachmentService>(
       new syncer::AttachmentServiceProxy(attachment_service_proxy_));
 }
 
 }  // namespace sync_driver