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

sync/syncable/scoped_kernel_lock.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_SCOPED_KERNEL_LOCK_H_
 #define SYNC_SYNCABLE_SCOPED_KERNEL_LOCK_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/synchronization/lock.h"
 
+namespace syncer {
 namespace syncable {
 
 class Directory;
 
 class ScopedKernelLock {
  public:
   explicit ScopedKernelLock(const Directory* dir);
   ~ScopedKernelLock() {}
 
   base::AutoLock scoped_lock_;
   Directory* const dir_;
   DISALLOW_COPY_AND_ASSIGN(ScopedKernelLock);
 };
 
 }  // namespace syncable
+}  // namespace syncer
 
 #endif  // SYNC_SYNCABLE_SCOPED_KERNEL_LOCK_H_