Migrate desktop_photo_search to top level (#1002)

desktop_photo_search/material/lib/src/unsplash/urls.dart

@@ -0,0 +1,44 @@
+// Copyright 2019 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:convert';
+
+import 'package:built_value/built_value.dart';
+import 'package:built_value/serializer.dart';
+
+import '../serializers.dart';
+
+part 'urls.g.dart';
+
+abstract class Urls implements Built<Urls, UrlsBuilder> {
+  factory Urls([void Function(UrlsBuilder b)? updates]) = _$Urls;
+
+  Urls._();
+
+  @BuiltValueField(wireName: 'raw')
+  String? get raw;
+
+  @BuiltValueField(wireName: 'full')
+  String? get full;
+
+  @BuiltValueField(wireName: 'regular')
+  String? get regular;
+
+  @BuiltValueField(wireName: 'small')
+  String? get small;
+
+  @BuiltValueField(wireName: 'thumb')
+  String? get thumb;
+
+  String toJson() {
+    return json.encode(serializers.serializeWith(Urls.serializer, this));
+  }
+
+  static Urls? fromJson(String jsonString) {
+    return serializers.deserializeWith(
+        Urls.serializer, json.decode(jsonString));
+  }
+
+  static Serializer<Urls> get serializer => _$urlsSerializer;
+}