Rename DesktopEngagement* to DesktopSessionDuration*.

chrome/browser/metrics/desktop_engagement/desktop_engagement_service.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 "chrome/browser/metrics/desktop_engagement/desktop_engagement_service.h"
-
-#include "base/bind.h"
-#include "base/metrics/histogram_macros.h"
-#include "base/strings/string_number_conversions.h"
-#include "components/variations/variations_associated_data.h"
-
-namespace metrics {
-
-namespace {
-
-DesktopEngagementService* g_instance = nullptr;
-
-}  // namespace
-
-// static
-void DesktopEngagementService::Initialize() {
-  g_instance = new DesktopEngagementService;
-}
-
-// static
-bool DesktopEngagementService::IsInitialized() {
-  return g_instance != nullptr;
-}
-
-// static
-DesktopEngagementService* DesktopEngagementService::Get() {
-  DCHECK(g_instance);
-  return g_instance;
-}
-
-void DesktopEngagementService::StartTimer(base::TimeDelta duration) {
-  timer_.Start(FROM_HERE, duration,
-               base::Bind(&DesktopEngagementService::OnTimerFired,
-                          weak_factory_.GetWeakPtr()));
-}
-
-void DesktopEngagementService::OnVisibilityChanged(bool visible) {
-  is_visible_ = visible;
-  if (is_visible_ && !is_first_session_) {
-    OnUserEvent();
-  } else if (in_session_ && !is_audio_playing_) {
-    DVLOG(4) << "Ending session due to visibility change";
-    EndSession();
-  }
-}
-
-void DesktopEngagementService::OnUserEvent() {
-  if (!is_visible_)
-    return;
-
-  last_user_event_ = base::TimeTicks::Now();
-  // This may start session.
-  if (!in_session_) {
-    DVLOG(4) << "Starting session due to user event";
-    StartSession();
-  }
-}
-
-void DesktopEngagementService::OnAudioStart() {
-  // This may start session.
-  is_audio_playing_ = true;
-  if (!in_session_) {
-    DVLOG(4) << "Starting session due to audio start";
-    StartSession();
-  }
-}
-
-void DesktopEngagementService::OnAudioEnd() {
-  is_audio_playing_ = false;
-
-  // If the timer is not running, this means that no user events happened in the
-  // last 5 minutes so the session can be terminated.
-  if (!timer_.IsRunning()) {
-    DVLOG(4) << "Ending session due to audio ending";
-    EndSession();
-  }
-}
-
-DesktopEngagementService::DesktopEngagementService()
-    : session_start_(base::TimeTicks::Now()),
-      last_user_event_(session_start_),
-      audio_tracker_(this),
-      weak_factory_(this) {
-  InitInactivityTimeout();
-}
-
-DesktopEngagementService::~DesktopEngagementService() {}
-
-void DesktopEngagementService::OnTimerFired() {
-  base::TimeDelta remaining =
-      inactivity_timeout_ - (base::TimeTicks::Now() - last_user_event_);
-  if (remaining.ToInternalValue() > 0) {
-    StartTimer(remaining);
-    return;
-  }
-
-  // No user events happened in the last 5 min. Terminate the session now.
-  if (!is_audio_playing_) {
-    DVLOG(4) << "Ending session after delay";
-    EndSession();
-  }
-}
-
-void DesktopEngagementService::StartSession() {
-  in_session_ = true;
-  is_first_session_ = false;
-  session_start_ = base::TimeTicks::Now();
-  StartTimer(inactivity_timeout_);
-}
-
-void DesktopEngagementService::EndSession() {
-  in_session_ = false;
-
-  base::TimeDelta delta = base::TimeTicks::Now() - session_start_;
-  DVLOG(4) << "Logging session length of " << delta.InSeconds() << " seconds.";
-
-  // Note: This metric is recorded separately for Android in
-  // UmaSessionStats::UmaEndSession.
-  UMA_HISTOGRAM_LONG_TIMES("Session.TotalDuration", delta);
-}
-
-void DesktopEngagementService::InitInactivityTimeout() {
-  const int kDefaultInactivityTimeoutMinutes = 5;
-
-  int timeout_minutes = kDefaultInactivityTimeoutMinutes;
-  std::string param_value = variations::GetVariationParamValue(
-      "DesktopEngagement", "inactivity_timeout");
-  if (!param_value.empty())
-    base::StringToInt(param_value, &timeout_minutes);
-
-  inactivity_timeout_ = base::TimeDelta::FromMinutes(timeout_minutes);
-}
-
-}  // namespace metrics