[Sync] Move //sync to //components/sync.

sync/engine/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_COMMIT_CONTRIBUTOR_H_
-#define SYNC_ENGINE_COMMIT_CONTRIBUTOR_H_
-
-#include <cstddef>
-#include <memory>
-
-#include "sync/base/sync_export.h"
-
-namespace syncer {
-
-class CommitContribution;
-
-namespace syncable {
-class Directory;
-}
-
-// This class represents a source of items to commit to the sync server.
-//
-// When asked, it can return CommitContribution objects that contain a set of
-// items to be committed from this source.
-class SYNC_EXPORT CommitContributor {
- public:
-  CommitContributor();
-  virtual ~CommitContributor() = 0;
-
-  // Gathers up to |max_entries| unsynced items from this contributor into a
-  // CommitContribution.  Returns NULL when the contributor has nothing to
-  // contribute.
-  virtual std::unique_ptr<CommitContribution> GetContribution(
-      size_t max_entries) = 0;
-};
-
-}  // namespace syncer
-
-#endif  // SYNC_ENGINE_COMMIT_CONTRIBUTOR_H_