move V2 classes in chrome/engine to syncer_v2 namespace

sync/internal_api/public/sync_context.h

 // Copyright 2014 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_INTERNAL_API_PUBLIC_SYNC_CONTEXT_H_
 #define SYNC_INTERNAL_API_PUBLIC_SYNC_CONTEXT_H_
 
 #include "base/basictypes.h"
 #include "base/memory/weak_ptr.h"
 #include "base/sequenced_task_runner.h"
 #include "sync/base/sync_export.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/internal_api/public/non_blocking_sync_common.h"
 
-namespace syncer {
+namespace syncer_v2 {
 class ModelTypeSyncProxyImpl;
-}
 
-namespace syncer_v2 {
 // An interface of the core parts of sync.
 //
 // In theory, this is the component that provides off-thread sync types with
 // functionality to schedule and execute communication with the sync server.  In
 // practice, this class delegates most of the responsibilty of implemeting this
 // functionality to other classes, and most of the interface is exposed not
 // directly here but instead through a per-ModelType class that this class helps
 // instantiate.
 class SYNC_EXPORT_PRIVATE SyncContext {
  public:
   SyncContext();
   virtual ~SyncContext();
 
   // Initializes the connection between the sync context on the sync thread and
   // a proxy for the specified non-blocking sync type that lives on the data
   // type's thread.
   virtual void ConnectSyncTypeToWorker(
       syncer::ModelType type,
       const DataTypeState& data_type_state,
       const UpdateResponseDataList& saved_pending_updates,
       const scoped_refptr<base::SequencedTaskRunner>& datatype_task_runner,
-      const base::WeakPtr<syncer::ModelTypeSyncProxyImpl>& type_sync_proxy) = 0;
+      const base::WeakPtr<ModelTypeSyncProxyImpl>& type_sync_proxy) = 0;
 
   // Disconnects the syncer from the model and stops syncing the type.
   //
   // By the time this is called, the model thread should have already
   // invalidated the WeakPtr it sent to us in the connect request.  Any
   // messages sent to that ModelTypeSyncProxy will not be recived.
   //
   // This is the sync thread's chance to clear state associated with the type.
   // It also causes the syncer to stop requesting updates for this type, and to
   // abort any in-progress commit requests.
   virtual void DisconnectSyncWorker(syncer::ModelType type) = 0;
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_SYNC_CONTEXT_H_