[Sync] USS: Load metadata into the processor.

Data still needs to be loaded, and then testing will be easier.

BUG=569645,569987

Review URL: https://codereview.chromium.org/1635693002

Cr-Commit-Position: refs/heads/master@{#372786}

2 files changed, 58 insertions, 3 deletions

diff --git a/sync/api/metadata_batch.cc b/sync/api/metadata_batch.cc
new file mode 100644
index 0000000..072ad5e
--- /dev/null
+++ b/sync/api/metadata_batch.cc
@@ -0,0 +1,29 @@
+// Copyright 2016 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/metadata_batch.h"
+
+namespace syncer_v2 {
+
+MetadataBatch::MetadataBatch() {}
+MetadataBatch::~MetadataBatch() {}
+
+EntityMetadataMap&& MetadataBatch::TakeAllMetadata() {
+  return std::move(metadata_map_);
+}
+
+void MetadataBatch::AddMetadata(const std::string& client_tag,
+                                const sync_pb::EntityMetadata& metadata) {
+  metadata_map_.insert(std::make_pair(client_tag, metadata));
+}
+
+const DataTypeState& MetadataBatch::GetDataTypeState() const {
+  return state_;
+}
+
+void MetadataBatch::SetDataTypeState(const DataTypeState& state) {
+  state_ = state;
+}
+
+}  // namespace syncer_v2
diff --git a/sync/api/metadata_batch.h b/sync/api/metadata_batch.h
index 459999c..56ab2a7 100644
--- a/sync/api/metadata_batch.h
+++ b/sync/api/metadata_batch.h
@@ -5,15 +5,41 @@
 #ifndef SYNC_API_METADATA_BATCH_H_
 #define SYNC_API_METADATA_BATCH_H_
 
+#include <map>
+
 #include "sync/base/sync_export.h"
+#include "sync/internal_api/public/non_blocking_sync_common.h"
+#include "sync/protocol/entity_metadata.pb.h"
 
 namespace syncer_v2 {
 
-// Interface used by the processor to read metadata requested from the service.
+// Map of client tag to EntityMetadata proto.
+typedef std::map<std::string, sync_pb::EntityMetadata> EntityMetadataMap;
+
+// Container used to pass sync metadata from services to their processor.
 class SYNC_EXPORT MetadataBatch {
  public:
-  MetadataBatch() {}
-  virtual ~MetadataBatch() {}
+  MetadataBatch();
+  virtual ~MetadataBatch();
+
+  // Allows the caller to take ownership of the entire metadata map. This is
+  // done because the caller will probably swap out all the EntityMetadata
+  // protos from the map for performance reasons.
+  EntityMetadataMap&& TakeAllMetadata();
+
+  // Add |metadata| for |client_tag| to the batch.
+  void AddMetadata(const std::string& client_tag,
+                   const sync_pb::EntityMetadata& metadata);
+
+  // Get the DataTypeState for this batch.
+  const DataTypeState& GetDataTypeState() const;
+
+  // Set the DataTypeState for this batch.
+  void SetDataTypeState(const DataTypeState& state);
+
+ private:
+  EntityMetadataMap metadata_map_;
+  DataTypeState state_;
 };
 
 }  // namespace syncer_v2