[Sync] Adding USS interfaces for processor-service communication.

Copying Sky's patch since he's out.

BUG=536895,543405

patch from issue 1444083002 at patchset 20001 (http://crrev.com/1444083002#ps20001)

Review URL: https://codereview.chromium.org/1462233002

Cr-Commit-Position: refs/heads/master@{#360885}

7 files changed, 159 insertions, 0 deletions

diff --git a/sync/api/data_batch.h b/sync/api/data_batch.h
new file mode 100644
index 0000000..63359cf
--- /dev/null
+++ b/sync/api/data_batch.h
@@ -0,0 +1,21 @@
+// 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_DATA_BATCH_H_
+#define SYNC_API_DATA_BATCH_H_
+
+#include "sync/base/sync_export.h"
+
+namespace syncer_v2 {
+
+// Interface used by the processor and service to communicate about data.
+class SYNC_EXPORT DataBatch {
+ public:
+  DataBatch() {}
+  virtual ~DataBatch() {}
+};
+
+}  // namespace syncer_v2
+
+#endif  // SYNC_API_DATA_BATCH_H_
diff --git a/sync/api/entity_data.h b/sync/api/entity_data.h
index 66a6a99..4fe88510 100644
--- a/sync/api/entity_data.h
+++ b/sync/api/entity_data.h
@@ -25,6 +25,7 @@ struct SYNC_EXPORT EntityDataTraits {
 };
 
 typedef syncer::ProtoValuePtr<EntityData, EntityDataTraits> EntityDataPtr;
+typedef std::vector<EntityDataPtr> EntityDataList;
 
 // A light-weight container for sync entity data which represents either
 // local data created on the ModelTypeService side or remote data created
diff --git a/sync/api/metadata_batch.h b/sync/api/metadata_batch.h
new file mode 100644
index 0000000..56ffffb
--- /dev/null
+++ b/sync/api/metadata_batch.h
@@ -0,0 +1,21 @@
+// 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_METADATA_BATCH_H_
+#define SYNC_API_METADATA_BATCH_H_
+
+#include "sync/base/sync_export.h"
+
+namespace syncer_v2 {
+
+// Interface used by the processor and service to communicate about metadata.
+class SYNC_EXPORT MetadataBatch {
+ public:
+  MetadataBatch() {}
+  virtual ~MetadataBatch() {}
+};
+
+}  // namespace syncer_v2
+
+#endif  // SYNC_API_METADATA_BATCH_H_
diff --git a/sync/api/metadata_changes.h b/sync/api/metadata_changes.h
new file mode 100644
index 0000000..a3d4d3b
--- /dev/null
+++ b/sync/api/metadata_changes.h
@@ -0,0 +1,21 @@
+// 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_METADATA_CHANGES_H_
+#define SYNC_API_METADATA_CHANGES_H_
+
+#include "sync/base/sync_export.h"
+
+namespace syncer_v2 {
+
+// Interface used by the processor and service to communicate about metadata.
+class SYNC_EXPORT MetadataChanges {
+ public:
+  MetadataChanges() {}
+  virtual ~MetadataChanges() {}
+};
+
+}  // namespace syncer_v2
+
+#endif  // SYNC_API_METADATA_CHANGES_H_
diff --git a/sync/api/model_type_change_processor.h b/sync/api/model_type_change_processor.h
index 85f8d16..7781a0e 100644
--- a/sync/api/model_type_change_processor.h
+++ b/sync/api/model_type_change_processor.h
@@ -5,16 +5,36 @@
 #ifndef SYNC_API_MODEL_TYPE_CHANGE_PROCESSOR_H_
 #define SYNC_API_MODEL_TYPE_CHANGE_PROCESSOR_H_
 
+#include <string>
+
+#include "base/memory/scoped_ptr.h"
+#include "sync/api/entity_data.h"
 #include "sync/base/sync_export.h"
 
+namespace syncer {
+class SyncError;
+}  // namespace syncer
+
 namespace syncer_v2 {
 
+class MetadataChanges;
+
 // Interface used by the ModelTypeService to inform sync of local
 // changes.
 class SYNC_EXPORT ModelTypeChangeProcessor {
  public:
   ModelTypeChangeProcessor();
   virtual ~ModelTypeChangeProcessor();
+
+  // Inform the processor of a new or updated entity.
+  virtual void Put(const std::string& client_key,
+                   const std::string& non_unique_name,
+                   const sync_pb::EntitySpecifics& specifics,
+                   MetadataChanges* metadata_changes) = 0;
+
+  // Inform the processor of a deleted entity.
+  virtual void Delete(const std::string& client_key,
+                      MetadataChanges* metadata_changes) = 0;
 };
 
 }  // namespace syncer_v2
diff --git a/sync/api/model_type_service.cc b/sync/api/model_type_service.cc
index 61ea860..759860a 100644
--- a/sync/api/model_type_service.cc
+++ b/sync/api/model_type_service.cc
@@ -10,4 +10,18 @@ ModelTypeService::ModelTypeService() {}
 
 ModelTypeService::~ModelTypeService() {}
 
+syncer_v2::ModelTypeChangeProcessor* ModelTypeService::change_processor() {
+  return change_processor_.get();
+}
+
+void ModelTypeService::set_change_processor(
+    scoped_ptr<syncer_v2::ModelTypeChangeProcessor> change_processor) {
+  DCHECK(!change_processor_);
+  change_processor_.swap(change_processor);
+}
+
+void ModelTypeService::clear_change_processor() {
+  change_processor_.reset();
+}
+
 }  // namespace syncer_v2
diff --git a/sync/api/model_type_service.h b/sync/api/model_type_service.h
index d01dc87..473c9c1 100644
--- a/sync/api/model_type_service.h
+++ b/sync/api/model_type_service.h
@@ -5,17 +5,78 @@
 #ifndef SYNC_API_MODEL_TYPE_SERVICE_H_
 #define SYNC_API_MODEL_TYPE_SERVICE_H_
 
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/memory/scoped_ptr.h"
+#include "sync/api/entity_data.h"
+#include "sync/api/model_type_change_processor.h"
 #include "sync/base/sync_export.h"
 
+namespace syncer {
+class SyncError;
+}  // namespace syncer
+
 namespace syncer_v2 {
 
+class DataBatch;
+class MetadataBatch;
+class MetadataChanges;
+
 // Interface implemented by model types to receive updates from sync via the
 // SharedModelTypeProcessor. Provides a way for sync to update the data and
 // metadata for entities, as well as the model type state.
 class SYNC_EXPORT ModelTypeService {
  public:
+  typedef base::Callback<void(syncer::SyncError, scoped_ptr<DataBatch>)>
+      DataCallback;
+  typedef base::Callback<void(syncer::SyncError, scoped_ptr<MetadataBatch>)>
+      MetadataCallback;
+  typedef std::vector<std::string> ClientKeyList;
+
   ModelTypeService();
+
   virtual ~ModelTypeService();
+
+  // Creates an object used to communicate changes in the sync metadata to the
+  // model type store.
+  virtual MetadataChanges* CreateMetadataChanges() = 0;
+
+  // Perform the initial merge of data from the sync server. Should only need
+  // to be called when sync is first turned on, not on every restart.
+  virtual syncer::SyncError MergeSyncData(MetadataChanges* metadata_changes,
+                                          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;
+
+  // Asynchronously retrieve the sync metadata.
+  virtual void LoadMetadata(MetadataCallback callback) = 0;
+
+  // Asynchronously retrieve the corresponding sync data for |client_keys|.
+  virtual void GetData(ClientKeyList client_keys, DataCallback callback) = 0;
+
+  // Asynchronously retrieve all of the local sync data.
+  virtual void GetAllData(DataCallback callback) = 0;
+
+  // Get or generate a client tag for |entity_data|.
+  virtual std::string GetClientTag(const EntityData* entity_data) = 0;
+
+  // TODO(skym): See crbug/547087, do we need all these accessors?
+  syncer_v2::ModelTypeChangeProcessor* change_processor();
+
+  void set_change_processor(
+      scoped_ptr<syncer_v2::ModelTypeChangeProcessor> change_processor);
+
+  void clear_change_processor();
+
+ private:
+  // Recieves ownership in set_change_processor(...).
+  scoped_ptr<syncer_v2::ModelTypeChangeProcessor> change_processor_;
 };
 
 }  // namespace syncer_v2