sync: Make BaseNode lookup-related Init functions return specific failures.

chrome/browser/sync/internal_api/write_node.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_SYNC_INTERNAL_API_WRITE_NODE_H_
 #define CHROME_BROWSER_SYNC_INTERNAL_API_WRITE_NODE_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 36 matching lines @@
 class WriteNode : public BaseNode {
  public:
   // Create a WriteNode using the given transaction.
   explicit WriteNode(WriteTransaction* transaction);
   virtual ~WriteNode();
 
   // A client must use one (and only one) of the following Init variants to
   // populate the node.
 
   // BaseNode implementation.
-  virtual bool InitByIdLookup(int64 id) OVERRIDE;
-  virtual bool InitByClientTagLookup(syncable::ModelType model_type,
-                                     const std::string& tag) OVERRIDE;
+  virtual InitByLookupResult InitByIdLookup(int64 id) OVERRIDE;
+  virtual InitByLookupResult InitByClientTagLookup(
+      syncable::ModelType model_type,
+      const std::string& tag) OVERRIDE;
 
   // Create a new node with the specified parent and predecessor.  |model_type|
   // dictates the type of the item, and controls which EntitySpecifics proto
   // extension can be used with this item.  Use a NULL |predecessor|
   // to indicate that this is to be the first child.
   // |predecessor| must be a child of |new_parent| or NULL. Returns false on
   // failure.
   bool InitByCreation(syncable::ModelType model_type,
                       const BaseNode& parent,
                       const BaseNode* predecessor);
 
   // Create nodes using this function if they're unique items that
   // you want to fetch using client_tag. Note that the behavior of these
   // items is slightly different than that of normal items.
   // Most importantly, if it exists locally, this function will
   // actually undelete it
   // Client unique tagged nodes must NOT be folders.
   bool InitUniqueByCreation(syncable::ModelType model_type,
                             const BaseNode& parent,
                             const std::string& client_tag);
 
   // Each server-created permanent node is tagged with a unique string.
   // Look up the node with the particular tag.  If it does not exist,
   // return false.
-  bool InitByTagLookup(const std::string& tag);
+  InitByLookupResult InitByTagLookup(const std::string& tag);
 
   // These Set() functions correspond to the Get() functions of BaseNode.
   void SetIsFolder(bool folder);
   void SetTitle(const std::wstring& title);
 
   // External ID is a client-only field, so setting it doesn't cause the item to
   // be synced again.
   void SetExternalId(int64 external_id);
 
   // Remove this node and its children.
@@ skipping 85 matching lines @@
 
   // The sync API transaction that is the parent of this node.
   WriteTransaction* transaction_;
 
   DISALLOW_COPY_AND_ASSIGN(WriteNode);
 };
 
 }  // namespace sync_api
 
 #endif  // CHROME_BROWSER_SYNC_INTERNAL_API_WRITE_NODE_H_