[Sync] Make GetFirstChildId return a flag indicating success

chrome/browser/sync/engine/nigori_util.h

 // 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.
 
 // Various utility methods for nigori-based multi-type encryption.
 
 #ifndef CHROME_BROWSER_SYNC_ENGINE_NIGORI_UTIL_H_
 #define CHROME_BROWSER_SYNC_ENGINE_NIGORI_UTIL_H_
 #pragma once
 
@@ skipping 37 matching lines @@
 // otherwise. Note: this does not check that already encrypted entries are
 // encrypted with the proper key.
 bool EntryNeedsEncryption(const ModelTypeSet& encrypted_types,
                           const Entry& entry);
 
 // Same as EntryNeedsEncryption, but looks at specifics.
 bool SpecificsNeedsEncryption(const ModelTypeSet& encrypted_types,
                               const sync_pb::EntitySpecifics& specifics);
 
 // Verifies all data of type |type| is encrypted appropriately.
-bool VerifyDataTypeEncryption(BaseTransaction* const trans,
-                              browser_sync::Cryptographer* cryptographer,
-                              ModelType type,
-                              bool is_encrypted);
+bool VerifyDataTypeEncryptionForTest(
+    BaseTransaction* const trans,
+    browser_sync::Cryptographer* cryptographer,
+    ModelType type,
+    bool is_encrypted);
 
 }  // namespace syncable
 
 #endif  // CHROME_BROWSER_SYNC_ENGINE_NIGORI_UTIL_H_