sync: Implement per-type commit interface

sync/engine/sync_directory_commit_contributor.h

+// Copyright (c) 2013 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_SYNC_DIRECTORY_COMMIT_CONTRIBUTOR_H_
+#define SYNC_ENGINE_SYNC_DIRECTORY_COMMIT_CONTRIBUTOR_H_
+
+#include <map>
+
+#include "sync/internal_api/public/base/model_type.h"
+
+namespace syncer {
+
+class SyncDirectoryCommitContribution;
+
+namespace syncable {
+class Directory;
+}
+
+class SyncDirectoryCommitContributor {

[Nicolas Zea, 2013/10/10 21:34:45]

Add comment about what this class is

[rlarocque, 2013/10/11 23:03:30]

Done.

+ public:
+  SyncDirectoryCommitContributor(syncable::Directory* dir, ModelType type);
+  ~SyncDirectoryCommitContributor();
+
+  SyncDirectoryCommitContribution* GetContribution(size_t max_entries);
+
+ private:
+  syncable::Directory* dir_;
+  ModelType type_;
+};
+
+// TODO(rlarocque): Find a better place for this definition.
+typedef std::map<ModelType, SyncDirectoryCommitContributor*>
+    CommitContributorMap;
+
+}  // namespace
+
+#endif  // SYNC_ENGINE_SYNC_DIRECTORY_COMMIT_CONTRIBUTOR_H_