Add platform_services sample (#8058)

* Add platform_services sample

* update build.gradle to use latest scripts

* use FlutterActivity

* Updated ExampleInstrumentedTest.java and deleted FlutterPlugin.groovy

* Remove getRandom code from main.dart

* remove unused import
diff --git a/examples/platform_services/lib/main.dart b/examples/platform_services/lib/main.dart
new file mode 100644
index 0000000..a0870d3
--- /dev/null
+++ b/examples/platform_services/lib/main.dart
@@ -0,0 +1,55 @@
+// 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.
+
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+
+class PlatformServices extends StatefulWidget {
+  @override
+  _PlatformServicesState createState() => new _PlatformServicesState();
+}
+
+class _PlatformServicesState extends State<PlatformServices> {
+  double _latitude;
+  double _longitude;
+
+  @override
+  Widget build(BuildContext context) {
+    return new Material(
+      child: new Center(
+        child: new Column(
+          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+          children: <Widget>[
+            new Text('Hello from Flutter!'),
+            new RaisedButton(
+              child: new Text('Get Location'),
+              onPressed: _getLocation
+            ),
+            new Text('Latitude: $_latitude, Longitude: $_longitude'),
+          ]
+        )
+      )
+    );
+  }
+
+  Future<Null> _getLocation() async {
+    final Map<String, String> message = <String, String>{'provider': 'network'};
+    final Map<String, dynamic> reply = await PlatformMessages.sendJSON('getLocation', message);
+    // If the widget was removed from the tree while the message was in flight,
+    // we want to discard the reply rather than calling setState to update our
+    // non-existent appearance.
+    if (!mounted)
+      return;
+    setState(() {
+      _latitude = reply['latitude'].toDouble();
+      _longitude = reply['longitude'].toDouble();
+    });
+  }
+}
+
+void main() {
+  runApp(new PlatformServices());
+}