[Sync] Move sync/{internal_api,syncable} into syncer namespace

sync/syncable/write_transaction_info.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 SYNC_SYNCABLE_WRITE_TRANSACTION_INFO_H_
 #define SYNC_SYNCABLE_WRITE_TRANSACTION_INFO_H_
 #pragma once
 
 #include "sync/syncable/base_transaction.h"
 #include "sync/syncable/entry_kernel.h"
 
+namespace syncer {
 namespace syncable {
 
 // A struct describing the changes made during a transaction.
 struct WriteTransactionInfo {
   WriteTransactionInfo(int64 id,
                        tracked_objects::Location location,
                        WriterTag writer,
                        ImmutableEntryKernelMutationMap mutations);
   WriteTransactionInfo();
   ~WriteTransactionInfo();
 
   // Caller owns the return value.
   base::DictionaryValue* ToValue(size_t max_mutations_size) const;
 
   int64 id;
   // If tracked_objects::Location becomes assignable, we can use that
   // instead.
   std::string location_string;
   WriterTag writer;
   ImmutableEntryKernelMutationMap mutations;
 };
 
 typedef
     syncer::Immutable<WriteTransactionInfo>
     ImmutableWriteTransactionInfo;
 
 }  // namespace syncable
+}  // namespace syncer
 
 #endif  // SYNC_SYNCABLE_WRITE_TRANSACTION_INFO_H_