move V2 classes in chrome/engine to syncer_v2 namespace

sync/internal_api/public/sync_context_proxy.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_PROXY_H_
 #define SYNC_INTERNAL_API_PUBLIC_SYNC_CONTEXT_PROXY_H_
 
 #include "base/memory/weak_ptr.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 {
 
 // Interface for the datatype integration logic from non-sync threads.
 //
 // See SyncContextProxyImpl for an actual implementation.
 class SYNC_EXPORT_PRIVATE SyncContextProxy {
  public:
   SyncContextProxy();
   virtual ~SyncContextProxy();
 
   // Attempts to connect a non-blocking type to the sync context.
   //
   // Must be called from the thread where the data type lives.
   virtual void ConnectTypeToSync(
       syncer::ModelType type,
       const DataTypeState& data_type_state,
       const UpdateResponseDataList& saved_pending_updates,
-      const base::WeakPtr<syncer::ModelTypeSyncProxyImpl>& type_sync_proxy) = 0;
+      const base::WeakPtr<ModelTypeSyncProxyImpl>& type_sync_proxy) = 0;
 
   // Tells the syncer that we're no longer interested in syncing this type.
   //
   // Once this takes effect, the syncer can assume that it will no longer
   // receive commit requests for this type.  It should also stop requesting
   // and applying updates for this type, too.
   virtual void Disconnect(syncer::ModelType type) = 0;
 
   // Creates a clone of this SyncContextProxy.
   virtual scoped_ptr<SyncContextProxy> Clone() const = 0;
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_SYNC_CONTEXT_PROXY_H_