Migrate desktop_photo_search to top level (#1002)

desktop_photo_search/material/lib/src/widgets/policy_dialog.dart

@@ -0,0 +1,74 @@
+// 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 'package:flutter/gestures.dart';
+import 'package:flutter/material.dart';
+import 'package:url_launcher/url_launcher.dart' as url_launcher;
+
+class PolicyDialog extends StatelessWidget {
+  const PolicyDialog({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+      title: const Text('Terms & Conditions'),
+      content: Column(
+        mainAxisSize: MainAxisSize.min,
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          RichText(
+            textAlign: TextAlign.left,
+            text: TextSpan(
+              text: '• ',
+              style: const TextStyle(color: Colors.black, fontSize: 18),
+              children: [
+                TextSpan(
+                  text: 'https://policies.google.com/terms',
+                  style: const TextStyle(
+                      fontWeight: FontWeight.bold, color: Colors.lightBlue),
+                  recognizer: TapGestureRecognizer()
+                    ..onTap = () async {
+                      const url = 'https://policies.google.com/terms';
+                      if (await url_launcher.canLaunch(url)) {
+                        await url_launcher.launch(url);
+                      }
+                    },
+                )
+              ],
+            ),
+          ),
+          RichText(
+            textAlign: TextAlign.left,
+            text: TextSpan(
+              text: '• ',
+              style: const TextStyle(color: Colors.black, fontSize: 18),
+              children: [
+                TextSpan(
+                  text: 'https://unsplash.com/terms',
+                  style: const TextStyle(
+                      fontWeight: FontWeight.bold, color: Colors.lightBlue),
+                  recognizer: TapGestureRecognizer()
+                    ..onTap = () async {
+                      const url = 'https://unsplash.com/terms';
+                      if (await url_launcher.canLaunch(url)) {
+                        await url_launcher.launch(url);
+                      }
+                    },
+                )
+              ],
+            ),
+          ),
+        ],
+      ),
+      actions: [
+        TextButton(
+          onPressed: () {
+            Navigator.of(context).pop();
+          },
+          child: const Text('CLOSE'),
+        ),
+      ],
+    );
+  }
+}