Rename DesktopEngagement* to DesktopSessionDuration*.

chrome/browser/metrics/desktop_session/desktop_session_observer.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_observer.h"
+#include "chrome/browser/metrics/desktop_session/desktop_session_observer.h"
 
-#include "chrome/browser/metrics/desktop_engagement/desktop_engagement_service.h"
+#include "chrome/browser/metrics/desktop_session/desktop_session_service.h"
 #include "content/public/browser/render_view_host.h"
 
-DEFINE_WEB_CONTENTS_USER_DATA_KEY(metrics::DesktopEngagementObserver);
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(metrics::DesktopSessionObserver);
 
 namespace metrics {
 
-DesktopEngagementObserver::DesktopEngagementObserver(
+DesktopSessionObserver::DesktopSessionObserver(
     content::WebContents* web_contents,
-    DesktopEngagementService* service)
+    DesktopSessionService* service)
     : content::WebContentsObserver(web_contents), service_(service) {
   RegisterInputEventObserver(web_contents->GetRenderViewHost());
 }
 
-DesktopEngagementObserver::~DesktopEngagementObserver() {}
+DesktopSessionObserver::~DesktopSessionObserver() {}
 
 // static
-DesktopEngagementObserver* DesktopEngagementObserver::CreateForWebContents(
+DesktopSessionObserver* DesktopSessionObserver::CreateForWebContents(
     content::WebContents* web_contents) {
   DCHECK(web_contents);
 
-  if (!DesktopEngagementService::IsInitialized())
+  if (!DesktopSessionService::IsInitialized())
     return nullptr;
 
-  DesktopEngagementObserver* observer = FromWebContents(web_contents);
+  DesktopSessionObserver* observer = FromWebContents(web_contents);
   if (!observer) {
-    observer = new DesktopEngagementObserver(web_contents,
-                                             DesktopEngagementService::Get());
+    observer =
+        new DesktopSessionObserver(web_contents, DesktopSessionService::Get());
     web_contents->SetUserData(UserDataKey(), observer);
   }
   return observer;
 }
 
-void DesktopEngagementObserver::RegisterInputEventObserver(
+void DesktopSessionObserver::RegisterInputEventObserver(
     content::RenderViewHost* host) {
   if (host != nullptr)
     host->GetWidget()->AddInputEventObserver(this);
 }
 
-void DesktopEngagementObserver::UnregisterInputEventObserver(
+void DesktopSessionObserver::UnregisterInputEventObserver(
     content::RenderViewHost* host) {
   if (host != nullptr)
     host->GetWidget()->RemoveInputEventObserver(this);
 }
 
-void DesktopEngagementObserver::OnInputEvent(
-    const blink::WebInputEvent& event) {
+void DesktopSessionObserver::OnInputEvent(const blink::WebInputEvent& event) {
   service_->OnUserEvent();
 }
 
-void DesktopEngagementObserver::RenderViewHostChanged(
+void DesktopSessionObserver::RenderViewHostChanged(
     content::RenderViewHost* old_host,
     content::RenderViewHost* new_host) {
   UnregisterInputEventObserver(old_host);
   RegisterInputEventObserver(new_host);
 }
 
 }  // namespace metrics