Make MediaSession a runtime-enabled feature on Desktop.

content/browser/media/android/media_session_uma_helper.cc

-// Copyright 2015 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 "content/browser/media/android/media_session_uma_helper.h"
-
-#include <utility>
-
-#include "base/metrics/histogram_base.h"
-#include "base/metrics/histogram_macros.h"
-#include "base/time/default_clock.h"
-
-namespace content {
-
-using HistogramBase = base::HistogramBase;
-
-MediaSessionUmaHelper::MediaSessionUmaHelper()
-    : clock_(new base::DefaultClock())
-{}
-
-MediaSessionUmaHelper::~MediaSessionUmaHelper()
-{}
-
-void MediaSessionUmaHelper::RecordSessionSuspended(
-    MediaSessionSuspendedSource source) const {
-  UMA_HISTOGRAM_ENUMERATION(
-      "Media.Session.Suspended",
-      static_cast<HistogramBase::Sample>(source),
-      static_cast<HistogramBase::Sample>(MediaSessionSuspendedSource::Count));
-}
-
-void MediaSessionUmaHelper::RecordRequestAudioFocusResult(bool result) const {
-  UMA_HISTOGRAM_BOOLEAN("Media.Session.RequestAudioFocusResult", result);
-}
-
-void MediaSessionUmaHelper::OnSessionActive() {
-  current_active_time_ = clock_->Now();
-}
-
-void MediaSessionUmaHelper::OnSessionSuspended() {
-  if (current_active_time_.is_null())
-    return;
-
-  total_active_time_ += clock_->Now() - current_active_time_;
-  current_active_time_ = base::Time();
-}
-
-void MediaSessionUmaHelper::OnSessionInactive() {
-  if (!current_active_time_.is_null()) {
-    total_active_time_ += clock_->Now() - current_active_time_;
-    current_active_time_ = base::Time();
-  }
-
-  if (total_active_time_.is_zero())
-    return;
-
-  UMA_HISTOGRAM_LONG_TIMES("Media.Session.ActiveTime", total_active_time_);
-  total_active_time_ = base::TimeDelta();
-}
-
-void MediaSessionUmaHelper::SetClockForTest(
-    scoped_ptr<base::Clock> testing_clock) {
-  clock_ = std::move(testing_clock);
-}
-
-}  // namespace content