[Sync] USS: Add EntityChange.

BUG=536895,543405

Review URL: https://codereview.chromium.org/1458013003

Cr-Commit-Position: refs/heads/master@{#361153}

3 files changed, 81 insertions, 2 deletions

diff --git a/sync/api/entity_change.cc b/sync/api/entity_change.cc
new file mode 100644
index 0000000..e2f2bed
--- /dev/null
+++ b/sync/api/entity_change.cc
@@ -0,0 +1,33 @@
+// Copyright 2015 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.
+
+#include "sync/api/entity_change.h"
+
+namespace syncer_v2 {
+
+// static
+EntityChange EntityChange::CreateAdd(std::string client_key,
+                                     EntityDataPtr data) {
+  return EntityChange(client_key, ACTION_ADD, data);
+}
+
+// static
+EntityChange EntityChange::CreateUpdate(std::string client_key,
+                                        EntityDataPtr data) {
+  return EntityChange(client_key, ACTION_UPDATE, data);
+}
+
+// static
+EntityChange EntityChange::CreateDelete(std::string client_key) {
+  return EntityChange(client_key, ACTION_DELETE, EntityDataPtr());
+}
+
+EntityChange::EntityChange(std::string client_key,
+                           ChangeType type,
+                           EntityDataPtr data)
+    : client_key_(client_key), type_(type), data_(data){};
+
+EntityChange::~EntityChange() {}
+
+}  // namespace syncer_v2
diff --git a/sync/api/entity_change.h b/sync/api/entity_change.h
new file mode 100644
index 0000000..88e3812
--- /dev/null
+++ b/sync/api/entity_change.h
@@ -0,0 +1,46 @@
+// Copyright 2015 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_API_ENTITY_CHANGE_H_
+#define SYNC_API_ENTITY_CHANGE_H_
+
+#include <string>
+#include <vector>
+
+#include "sync/api/entity_data.h"
+#include "sync/base/sync_export.h"
+
+namespace syncer_v2 {
+
+class SYNC_EXPORT EntityChange {
+ public:
+  enum ChangeType {
+    ACTION_ADD,
+    ACTION_UPDATE,
+    ACTION_DELETE
+  };
+
+  static EntityChange CreateAdd(std::string client_key, EntityDataPtr data);
+  static EntityChange CreateUpdate(std::string client_key, EntityDataPtr data);
+  static EntityChange CreateDelete(std::string client_key);
+
+  virtual ~EntityChange();
+
+  std::string client_key() const { return client_key_; }
+  ChangeType type() const { return type_; }
+  const EntityData& data() const { return data_.value(); }
+
+ private:
+  EntityChange(std::string client_key, ChangeType type, EntityDataPtr data);
+
+  const std::string client_key_;
+  const ChangeType type_;
+  const EntityDataPtr data_;
+};
+
+typedef std::vector<EntityChange> EntityChangeList;
+
+}  // namespace syncer_v2
+
+#endif  // SYNC_API_ENTITY_CHANGE_H_
diff --git a/sync/api/model_type_service.h b/sync/api/model_type_service.h
index 473c9c1..c09271b 100644
--- a/sync/api/model_type_service.h
+++ b/sync/api/model_type_service.h
@@ -10,6 +10,7 @@
 
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
+#include "sync/api/entity_change.h"
 #include "sync/api/entity_data.h"
 #include "sync/api/model_type_change_processor.h"
 #include "sync/base/sync_export.h"
@@ -49,10 +50,9 @@ class SYNC_EXPORT ModelTypeService {
                                           EntityDataList entity_data_list) = 0;
 
   // Apply changes from the sync server locally.
-  // TODO(skym): The change type should be in here somehow.
   virtual syncer::SyncError ApplySyncChanges(
       MetadataChanges* metadata_changes,
-      EntityDataList entity_data_list) = 0;
+      EntityChangeList entity_changes) = 0;
 
   // Asynchronously retrieve the sync metadata.
   virtual void LoadMetadata(MetadataCallback callback) = 0;