Configuring travis to build Android. (#206)

add_to_app/flutter_module_using_plugin/lib/main.dart

@@ -24,7 +24,7 @@ void main() {
 }
 
 /// A simple model that uses a [MethodChannel] as the source of truth for the
-/// state of the counter.
+/// state of a counter.
 ///
 /// Rather than storing app state data within the Flutter module itself (where
 /// the native portions of the app can't access it), this module passes messages

add_to_app/flutter_module_using_plugin/test/widget_test.dart

@@ -9,13 +9,28 @@ import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 import 'package:flutter_module_using_plugin/main.dart';
+import 'package:provider/provider.dart';
+
+class MockCounterModel extends ChangeNotifier implements CounterModel {
+  int _count = 0;
+
+  int get count => _count;
+
+  void increment() {
+    _count++;
+    notifyListeners();
+  }
+}
 
 void main() {
   testWidgets('MiniView smoke test', (WidgetTester tester) async {
     // Build our app and trigger a frame.
     await tester.pumpWidget(
       MaterialApp(
-        home: Contents(),
+        home: ChangeNotifierProvider<CounterModel>.value(
+          value: MockCounterModel(),
+          child: Contents(),
+        ),
       ),
     );