[USS] Implement SharedModelTypeProcessor::GetAllNodes for USS

components/sync/protocol/proto_value_conversions.h

Index: components/sync/protocol/proto_value_conversions.h
diff --git a/components/sync/protocol/proto_value_conversions.h b/components/sync/protocol/proto_value_conversions.h
index 1391a887d8e1ddc9b0cde6e02819e3e87a5d7ec6..2cde10ee7112de0646485da1a1758aa4f7e160e9 100644
--- a/components/sync/protocol/proto_value_conversions.h
+++ b/components/sync/protocol/proto_value_conversions.h
@@ -37,6 +37,7 @@ class DeviceInfoSpecifics;
 class DeviceInformation;
 class DictionarySpecifics;
 class EncryptedData;
+class EntityMetadata;
 class EntitySpecifics;
 class EverythingDirective;
 class ExperimentsSpecifics;
@@ -300,6 +301,9 @@ std::unique_ptr<base::DictionaryValue> ClientConfigParamsToValue(
 std::unique_ptr<base::DictionaryValue> AttachmentIdProtoToValue(
     const sync_pb::AttachmentIdProto& proto);
 
+std::unique_ptr<base::DictionaryValue> EntityMetadataToValue(
+    const sync_pb::EntityMetadata& metadata);
+
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_PROTOCOL_PROTO_VALUE_CONVERSIONS_H_