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

chrome/browser/sync/glue/bookmark_model_associator.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/glue/bookmark_model_associator.h"
 
 #include <stack>
 
 #include "base/command_line.h"
 #include "base/hash_tables.h"
@@ skipping 257 matching lines @@
   }
 
   sync_api::ReadNode synced_bookmarks_node(&trans);
   if (has_synced_folder &&
       !synced_bookmarks_node.InitByIdLookup(synced_bookmarks_sync_id)) {
     return false;
   }
 
   // Sync model has user created nodes if either one of the permanent nodes
   // has children.
-  *has_nodes = bookmark_bar_node.GetFirstChildId() != sync_api::kInvalidId ||
-      other_bookmarks_node.GetFirstChildId() != sync_api::kInvalidId ||
-      (has_synced_folder &&
-          synced_bookmarks_node.GetFirstChildId() != sync_api::kInvalidId);
+  *has_nodes = bookmark_bar_node.HasChildren() ||
+      other_bookmarks_node.HasChildren() ||
+      (has_synced_folder && synced_bookmarks_node.HasChildren());
   return true;
 }
 
 bool BookmarkModelAssociator::NodesMatch(
     const BookmarkNode* bookmark,
     const sync_api::BaseNode* sync_node) const {
   if (bookmark->GetTitle() != UTF8ToUTF16(sync_node->GetTitle()))
     return false;
   if (bookmark->is_folder() != sync_node->GetIsFolder())
     return false;
@@ skipping 316 matching lines @@
 bool BookmarkModelAssociator::CryptoReadyIfNecessary() {
   // We only access the cryptographer while holding a transaction.
   sync_api::ReadTransaction trans(FROM_HERE, user_share_);
   const syncable::ModelTypeSet& encrypted_types =
       sync_api::GetEncryptedTypes(&trans);
   return encrypted_types.count(syncable::BOOKMARKS) == 0 ||
       trans.GetCryptographer()->is_ready();
 }
 
 }  // namespace browser_sync