Create and integrate a metrics service client into Blimp engine.

blimp/engine/app/blimp_metrics_service_client.h

+// 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.
+
+#ifndef BLIMP_ENGINE_APP_BLIMP_METRICS_SERVICE_CLIENT_H_
+#define BLIMP_ENGINE_APP_BLIMP_METRICS_SERVICE_CLIENT_H_
+
+#include <stdint.h>
+
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "components/metrics/metrics_service_client.h"
+
+class PrefService;
+
+namespace metrics {
+class MetricsService;
+class MetricsStateManager;
+class SystemProfileProto;
+}
+
+namespace net {
+class URLRequestContextGetter;
+}  // namespace net
+
+namespace blimp {
+namespace engine {
+
+// BlimpMetricsServiceClient provides an implementation of MetricsServiceClient

[Kevin M, 2016/05/11 17:08:42]

Can you add a comment explaining why we need this?

[Jess, 2016/05/11 20:17:30]

Added explanation of why.  Please take a look and let me know if I am assuming
too much context.

+// tailored for the Blimp engine.
+// Metrics are always turned on.
+class BlimpMetricsServiceClient : public metrics::MetricsServiceClient {
+ public:
+  // PrefService ownership is retained by the caller.
+  // The request_context_getter is a system request context.
+  // Both must remain valid for client lifetime.
+  BlimpMetricsServiceClient(
+      PrefService* pref_service,
+      scoped_refptr<net::URLRequestContextGetter> request_context_getter);
+  ~BlimpMetricsServiceClient() override;
+
+  // metrics::MetricsServiceClient implementation.
+  metrics::MetricsService* GetMetricsService() override;
+  void SetMetricsClientId(const std::string& client_id) override;
+  void OnRecordingDisabled() override;
+  bool IsOffTheRecordSessionActive() override;
+  int32_t GetProduct() override;
+  std::string GetApplicationLocale() override;
+  bool GetBrand(std::string* brand_code) override;
+  metrics::SystemProfileProto::Channel GetChannel() override;
+  std::string GetVersionString() override;
+  void OnLogUploadComplete() override;
+  void InitializeSystemProfileMetrics(
+      const base::Closure& done_callback) override;
+  void CollectFinalMetricsForLog(const base::Closure& done_callback) override;
+  std::unique_ptr<metrics::MetricsLogUploader> CreateUploader(
+      const base::Callback<void(int)>& on_upload_complete) override;
+  base::TimeDelta GetStandardUploadInterval() override;
+  metrics::MetricsServiceClient::EnableMetricsDefault GetDefaultOptIn()
+      override;
+
+ private:
+  // Used by NetMetricsLogUploader to create log-upload requests.
+  scoped_refptr<net::URLRequestContextGetter> request_context_getter_;
+
+  std::unique_ptr<metrics::MetricsStateManager> metrics_state_manager_;
+  std::unique_ptr<metrics::MetricsService> metrics_service_;
+
+  DISALLOW_COPY_AND_ASSIGN(BlimpMetricsServiceClient);
+};
+
+}  // namespace engine
+}  // namespace blimp
+
+#endif  // BLIMP_ENGINE_APP_BLIMP_METRICS_SERVICE_CLIENT_H_