Gather stability prefs into managing objects.

components/metrics/environment_recorder.h

+// Copyright 2017 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_ENVIRONMENT_RECORDER_H_
+#define COMPONENTS_METRICS_ENVIRONMENT_RECORDER_H_
+
+#include <string>
+
+#include "base/macros.h"
+
+class PrefService;
+class PrefRegistrySimple;
+
+namespace metrics {
+
+class SystemProfileProto;
+
+// Stores and loads system information to prefs for stability logs.

[rkaplow, 2017/02/14 20:11:19]

to and from prefs for ... ?

[Steven Holte, 2017/02/15 22:42:09]

Expanded comment.

+class EnvironmentRecorder {
+ public:
+  explicit EnvironmentRecorder(PrefService* local_state);
+  ~EnvironmentRecorder();
+
+  std::string RecordEnvironmentToPrefs(

[rkaplow, 2017/02/14 20:11:19]

cna you also mention returns empty string if it was unable to be serialized

[rkaplow, 2017/02/14 20:11:19]

prefer some comments - not obvious what string this is returning. Looking at
implementation, maybe should also change the name to mention it's returning the
serialized env?

[Steven Holte, 2017/02/15 22:42:09]

Done.

[Steven Holte, 2017/02/15 22:42:09]

Done.

+      const SystemProfileProto& system_profile);
+  bool LoadEnvironmentFromPrefs(SystemProfileProto* system_profile);

[rkaplow, 2017/02/14 20:11:19]

similar, mention what is this returning (and it's recording into the input
|system_profile|)

[Steven Holte, 2017/02/15 22:42:09]

Done.

+  void ClearEnvironmentFromPrefs();
+
+  int64_t GetLastBuildtime();
+  std::string GetLastVersion();
+  void SetBuildtimeAndVersion(int64_t buildtime, const std::string& version);
+
+  static void RegisterPrefs(PrefRegistrySimple* registry);

[rkaplow, 2017/02/14 20:11:19]

I havn't done a ton of pref logic, so maybe this is how people refer to it, but
would InitializePrefs be a better name?

[Steven Holte, 2017/02/15 22:42:09]

No, this is a fairly common name.  It is describing the prefs to a registry,
rather than creating the data in the file.

+
+ private:
+  PrefService* local_state_;
+
+  DISALLOW_COPY_AND_ASSIGN(EnvironmentRecorder);
+};
+
+}  // namespace metrics
+
+#endif  // COMPONENTS_METRICS_ENVIRONMENT_RECORDER_H_