mojo: add some end-to-end shell tests and a new test sample app

mojo/services/test_service/toy_monitoring_service.mojom

+// Copyright 2014 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.
+
+module mojo.test {
+
+// Various counters that services can periodically send to a
+// ToyMonitoringService for recording.
+struct ServiceStats {
+  uint64 num_new_requests;
+  double health;
+};
+
+// A per-service summary of all the ServiceStats the ToyMonitoringService has
+// observed.
+struct ServiceReport {
+  string service_name;
+  uint64 total_requests;
+  double mean_health;
+};
+
+// A simple interface to obtain a "report" from all services that have
+// opted to connect themselves for monitoring.
+interface ToyMonitoringService {
+  GetReport() => (ServiceReport[] report);
+};
+
+// ToyMonitoringServiceStatsRecorder records ServiceStats for an individual
+// service connection for aggregation in a ToyMonitoringService.
+[Client=ToyMonitoringServiceStatsUploader]
+interface ToyMonitoringServiceStatsRecorder {
+  // Upload a ServiceStats for monitoring.
+  RecordStats(uint64 client_id,
+              ServiceStats stats);
+};
+
+// The client-side contract for uploading ServiceStats to a
+// ToyMonitoringServiceStatsRecorder.
+interface ToyMonitoringServiceStatsUploader {
+  const uint64 kInvalidId = 0;
+  // Handshake to tell the client its global identifier and get the name.
+  SetIdAndReturnName(uint64 id) => (string service_name);
+};
+
+}  // module mojo.test