Move tracked prefs into services/preferences/tracked.

services/preferences/public/cpp/tracked/configuration.cc

+// 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.
+
+#include "services/preferences/public/cpp/tracked/configuration.h"
+
+namespace prefs {
+
+mojom::TrackedPreferenceMetadataPtr ConstructTrackedMetadata(
+    const TrackedPreferenceMetadata& metadata) {
+  return {base::in_place,    metadata.reporting_id,

[gab, 2017/03/29 16:27:57]

Why base::in_place? Are these using base::Optional under the hood?

[Sam McNally, 2017/03/30 02:23:23]

Switched to mojom::TrackedPreferenceMetadata::New() instead.

+          metadata.name,     metadata.enforcement_level,
+          metadata.strategy, metadata.value_type};
+}
+
+std::vector<mojom::TrackedPreferenceMetadataPtr> CloneTrackedConfiguration(
+    const std::vector<mojom::TrackedPreferenceMetadataPtr>& configuration) {
+  std::vector<mojom::TrackedPreferenceMetadataPtr> result;
+  for (const auto& metadata : configuration) {
+    result.push_back(metadata.Clone());
+  }
+  return result;
+}
+
+}  // namespace prefs