[Sync] Add HasChildren() function and use it instead of GetFirstChildId()

chrome/browser/sync/internal_api/base_node.cc

 // Copyright (c) 2011 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 "chrome/browser/sync/internal_api/base_node.h"
 
 #include "base/base64.h"
 #include "base/sha1.h"
 #include "base/string_number_conversions.h"
 #include "base/utf_string_conversions.h"
@@ skipping 183 matching lines @@
     ServerNameToSyncAPIName(GetEntry()->Get(syncable::NON_UNIQUE_NAME),
                             &result);
   }
   return result;
 }
 
 GURL BaseNode::GetURL() const {
   return GURL(GetBookmarkSpecifics().url());
 }
 
+bool BaseNode::HasChildren() const {
+  syncable::Directory* dir = GetTransaction()->GetLookup();
+  syncable::BaseTransaction* trans = GetTransaction()->GetWrappedTrans();
+  return dir->HasChildren(trans, GetEntry()->Get(syncable::ID));
+}
+
 int64 BaseNode::GetPredecessorId() const {
   syncable::Id id_string = GetEntry()->Get(syncable::PREV_ID);
   if (id_string.IsRoot())
     return kInvalidId;
   return IdToMetahandle(GetTransaction()->GetWrappedTrans(), id_string);
 }
 
 int64 BaseNode::GetSuccessorId() const {
   syncable::Id id_string = GetEntry()->Get(syncable::NEXT_ID);
   if (id_string.IsRoot())
@@ skipping 115 matching lines @@
     const sync_pb::EntitySpecifics& specifics) {
   syncable::ModelType type = syncable::GetModelTypeFromSpecifics(specifics);
   DCHECK_NE(syncable::UNSPECIFIED, type);
   if (GetModelType() != syncable::UNSPECIFIED) {
     DCHECK_EQ(GetModelType(), type);
   }
   unencrypted_data_.CopyFrom(specifics);
 }
 
 }  // namespace sync_api