[translate] Add translate ranker model loader.

components/translate/core/browser/translate_ranker_metrics_provider.cc

-// 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.
-
-#include "components/translate/core/browser/translate_ranker_metrics_provider.h"
-
-#include "base/metrics/histogram_macros.h"
-#include "components/metrics/proto/chrome_user_metrics_extension.pb.h"
-#include "components/metrics/proto/translate_event.pb.h"
-#include "components/translate/core/browser/proto/translate_ranker_model.pb.h"
-#include "components/translate/core/browser/translate_ranker.h"
-
-namespace translate {
-
-TranslateRankerMetricsProvider::TranslateRankerMetricsProvider() {}
-TranslateRankerMetricsProvider::~TranslateRankerMetricsProvider() {}
-
-void TranslateRankerMetricsProvider::ProvideGeneralMetrics(
-    metrics::ChromeUserMetricsExtension* uma_proto) {
-  TranslateRanker* translate_ranker = TranslateRanker::GetInstance();
-  if (translate_ranker != nullptr) {
-    std::vector<metrics::TranslateEventProto> translate_events;
-    translate_ranker->FlushTranslateEvents(&translate_events);
-    for (metrics::TranslateEventProto& event : translate_events) {
-      uma_proto->add_translate_event()->Swap(&event);
-    }
-
-    if (TranslateRanker::IsEnabled()) {
-      // TODO(hamelphi): Remove this logging once we start using
-      // TranslateEventProtos.
-      UMA_HISTOGRAM_SPARSE_SLOWLY("Translate.Ranker.Model.Version",
-                                  translate_ranker->GetModelVersion());
-    }
-  }
-}
-
-}  // namespace translate