Convert //sync from scoped_ptr to std::unique_ptr

sync/engine/directory_commit_contributor.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_ENGINE_DIRECTORY_COMMIT_CONTRIBUTOR_H_
 #define SYNC_ENGINE_DIRECTORY_COMMIT_CONTRIBUTOR_H_
 
 #include <stddef.h>
 
 #include <map>
+#include <memory>
 
 #include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
 #include "sync/engine/commit_contributor.h"
 #include "sync/engine/directory_commit_contribution.h"
 #include "sync/internal_api/public/base/model_type.h"
 
 namespace syncer {
 
 namespace syncable {
 class Directory;
 }
 
 class DirectoryTypeDebugInfoEmitter;
 
 // This class represents the syncable::Directory as a source of items to commit
 // to the sync server.
 //
 // Each instance of this class represents a particular type within the
 // syncable::Directory.  When asked, it will iterate through the directory, grab
 // any items of its type that are ready for commit, and return them in the form
 // of a DirectoryCommitContribution.
 class DirectoryCommitContributor : public CommitContributor {
  public:
   DirectoryCommitContributor(syncable::Directory* dir,
                              ModelType type,
                              DirectoryTypeDebugInfoEmitter* debug_info_emitter);
   ~DirectoryCommitContributor() override;
 
-  scoped_ptr<CommitContribution> GetContribution(size_t max_entries) override;
+  std::unique_ptr<CommitContribution> GetContribution(
+      size_t max_entries) override;
 
  private:
   syncable::Directory* dir_;
   ModelType type_;
 
   DirectoryTypeDebugInfoEmitter* debug_info_emitter_;
 
   DISALLOW_COPY_AND_ASSIGN(DirectoryCommitContributor);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_ENGINE_DIRECTORY_COMMIT_CONTRIBUTOR_H_