Convert //sync from scoped_ptr to std::unique_ptr

sync/internal_api/public/test/null_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_TEST_NULL_SYNC_CONTEXT_PROXY_H_
 #define SYNC_INTERNAL_API_PUBLIC_TEST_NULL_SYNC_CONTEXT_PROXY_H_
 
 #include "sync/internal_api/public/sync_context_proxy.h"
 
 namespace syncer_v2 {
 
 // A non-functional implementation of SyncContextProxy.
 //
 // It supports Clone(), but not much else.  Useful for testing.
 class NullSyncContextProxy : public SyncContextProxy {
  public:
   NullSyncContextProxy();
   ~NullSyncContextProxy() override;
 
   void ConnectTypeToSync(
       syncer::ModelType type,
-      scoped_ptr<ActivationContext> activation_context) override;
+      std::unique_ptr<ActivationContext> activation_context) override;
   void Disconnect(syncer::ModelType type) override;
-  scoped_ptr<SyncContextProxy> Clone() const override;
+  std::unique_ptr<SyncContextProxy> Clone() const override;
 };
 
 }  // namespace syncer_v2
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_TEST_NULL_SYNC_CONTEXT_PROXY_H_