Introduce MetricsServiceClient and ChromeMetricsServiceClient.

components/metrics/metrics_service_client.h

Index: components/metrics/metrics_service_client.h
===================================================================
--- components/metrics/metrics_service_client.h	(revision 0)
+++ components/metrics/metrics_service_client.h	(working copy)
@@ -0,0 +1,44 @@
+// 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.
+
+#ifndef COMPONENTS_METRICS_METRICS_SERVICE_CLIENT_H_
+#define COMPONENTS_METRICS_METRICS_SERVICE_CLIENT_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "components/metrics/proto/system_profile.pb.h"
+
+namespace metrics {
+
+// An abstraction of operations that depend on the embedder's (e.g. Chrome)
+// environment.
+class MetricsServiceClient {
+ public:
+  virtual ~MetricsServiceClient() {}
+
+  // Register the client id with other services (e.g. crash reporting), called
+  // when metrics recording gets enabled.
+  virtual void SetClientID(const std::string& client_id) = 0;
+
+  // Whether there's an "off the record" (aka "Incognito") session active.
+  virtual bool IsOffTheRecordSessionActive() = 0;
+
+  // Returns the current application locale (e.g. "en-US").
+  virtual std::string GetApplicationLocale() = 0;
+
+  // Retrieves the brand code string associated with the install, returning
+  // false if no brand code is available.
+  virtual bool GetBrand(std::string* brand_code) = 0;
+
+  // Returns the release channel (e.g. stable, beta, etc) of the application.
+  virtual SystemProfileProto::Channel GetChannel() = 0;
+
+  // Returns the version of the application as a string.
+  virtual std::string GetVersionString() = 0;
+};
+
+}  // namespace metrics
+
+#endif  // COMPONENTS_METRICS_METRICS_SERVICE_CLIENT_H_