Rename DesktopEngagement* to DesktopSessionDuration*.

chrome/browser/metrics/desktop_session/desktop_session_service.h

 // 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.
 
-#ifndef CHROME_BROWSER_METRICS_DESKTOP_ENGAGEMENT_DESKTOP_ENGAGEMENT_SERVICE_H_
-#define CHROME_BROWSER_METRICS_DESKTOP_ENGAGEMENT_DESKTOP_ENGAGEMENT_SERVICE_H_
+#ifndef CHROME_BROWSER_METRICS_DESKTOP_SESSION_DESKTOP_SESSION_SERVICE_H_
+#define CHROME_BROWSER_METRICS_DESKTOP_SESSION_DESKTOP_SESSION_SERVICE_H_
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
-#include "chrome/browser/metrics/desktop_engagement/audible_contents_tracker.h"
-#include "chrome/browser/metrics/desktop_engagement/chrome_visibility_observer.h"
+#include "chrome/browser/metrics/desktop_session/audible_contents_tracker.h"
+#include "chrome/browser/metrics/desktop_session/chrome_visibility_observer.h"
 
 namespace metrics {
 
-// Class for tracking and recording user engagement based on browser visibility,
-// audio and user interaction.
-class DesktopEngagementService : public AudibleContentsTracker::Observer {
+// Class for tracking and recording session length on desktop based on browser
+// visibility, audio and user interaction.
+class DesktopSessionService : public AudibleContentsTracker::Observer {

[sky, 2016/09/14 00:00:12]

This name is easily confused with session restore. Can you use something more
metrics/observer specific?

  public:
-  // Creates the |DesktopEngagementService| instance and initializes the
-  // observes that notify to it.
+  // Creates the |DesktopSessionService| instance and initializes the
+  // observers that notify to it.
   static void Initialize();
 
-  // Returns true if the |DesktopEngagementService| instance has been created.
+  // Returns true if the |DesktopSessionService| instance has been created.
   static bool IsInitialized();
 
-  // Returns the |DesktopEngagementService| instance.
-  static DesktopEngagementService* Get();
+  // Returns the |DesktopSessionService| instance.
+  static DesktopSessionService* Get();
 
   // Called when user interaction with the browser is caught.
   void OnUserEvent();
 
   // Called when visibility of the browser changes.
   void OnVisibilityChanged(bool visible);
 
   bool is_visible() const { return is_visible_; }
   bool in_session() const { return in_session_; }
   bool is_audio_playing() const { return is_audio_playing_; }
 
   void SetInactivityTimeoutForTesting(int seconds) {
     inactivity_timeout_ = base::TimeDelta::FromSeconds(seconds);
   }
 
  protected:
-  DesktopEngagementService();
-  ~DesktopEngagementService() override;
+  DesktopSessionService();
+  ~DesktopSessionService() override;
 
   // AudibleContentsTracker::Observer
   void OnAudioStart() override;
   void OnAudioEnd() override;
 
   // Decides whether session should be ended. Called when timer for inactivity
   // timeout was fired. Overridden by tests.
   virtual void OnTimerFired();
 
  private:
@@ skipping 22 matching lines @@
   bool is_first_session_ = true;
 
   // Timeout for waiting for user interaction.
   base::TimeDelta inactivity_timeout_;
 
   base::OneShotTimer timer_;
 
   ChromeVisibilityObserver visibility_observer_;
   AudibleContentsTracker audio_tracker_;
 
-  base::WeakPtrFactory<DesktopEngagementService> weak_factory_;
+  base::WeakPtrFactory<DesktopSessionService> weak_factory_;
 
-  DISALLOW_COPY_AND_ASSIGN(DesktopEngagementService);
+  DISALLOW_COPY_AND_ASSIGN(DesktopSessionService);
 };
 
 }  // namespace metrics
 
-#endif  // CHROME_BROWSER_METRICS_DESKTOP_ENGAGEMENT_DESKTOP_ENGAGEMENT_SERVICE_H_
+#endif  // CHROME_BROWSER_METRICS_DESKTOP_SESSION_DESKTOP_SESSION_SERVICE_H_