Construct the site engagement helper with a site engagement service.

chrome/browser/engagement/site_engagement_helper.cc

Index: chrome/browser/engagement/site_engagement_helper.cc
diff --git a/chrome/browser/engagement/site_engagement_helper.cc b/chrome/browser/engagement/site_engagement_helper.cc
index 6e5f9400e4c04db18bbde4a222b3daa66ba79a9b..5cda08daba39331ecc44a0d740ab3be8aef1e822 100644
--- a/chrome/browser/engagement/site_engagement_helper.cc
+++ b/chrome/browser/engagement/site_engagement_helper.cc
@@ -162,37 +162,27 @@ SiteEngagementService::Helper::~Helper() {
   }
 }
 
-SiteEngagementService::Helper::Helper(content::WebContents* web_contents)
+SiteEngagementService::Helper::Helper(content::WebContents* web_contents,
+                                      SiteEngagementService* service)
     : content::WebContentsObserver(web_contents),
       input_tracker_(this, web_contents),
       media_tracker_(this, web_contents),
+      service_(service),

[calamity, 2016/06/09 01:41:19]

Can we use the web_contents->browser_context() to get the service here instead?

[dominickn, 2016/06/09 03:25:47]

Done.

       record_engagement_(false) {}
 
 void SiteEngagementService::Helper::RecordUserInput(
     SiteEngagementMetrics::EngagementType type) {
   TRACE_EVENT0("SiteEngagement", "RecordUserInput");
   content::WebContents* contents = web_contents();
-  if (contents) {
-    Profile* profile =
-        Profile::FromBrowserContext(contents->GetBrowserContext());
-    SiteEngagementService* service = SiteEngagementService::Get(profile);
-
-    // Service is null in incognito.
-    if (service)
-      service->HandleUserInput(contents->GetVisibleURL(), type);
-  }
+  // Service is null in incognito.
+  if (contents && service_)
+    service_->HandleUserInput(contents, type);
 }
 
 void SiteEngagementService::Helper::RecordMediaPlaying(bool is_hidden) {
   content::WebContents* contents = web_contents();
-  if (contents) {
-    Profile* profile =
-        Profile::FromBrowserContext(contents->GetBrowserContext());
-    SiteEngagementService* service = SiteEngagementService::Get(profile);
-
-    if (service)
-      service->HandleMediaPlaying(contents->GetVisibleURL(), is_hidden);
-  }
+  if (contents && service_)
+    service_->HandleMediaPlaying(contents, is_hidden);
 }
 
 void SiteEngagementService::Helper::DidFinishNavigation(
@@ -224,12 +214,8 @@ void SiteEngagementService::Helper::DidFinishNavigation(
   if (prerender::PrerenderContents::FromWebContents(web_contents()) != nullptr)
     return;
 
-  Profile* profile =
-      Profile::FromBrowserContext(web_contents()->GetBrowserContext());
-  SiteEngagementService* service = SiteEngagementService::Get(profile);
-
-  if (service)
-    service->HandleNavigation(handle->GetURL(), handle->GetPageTransition());
+  if (service_)
+    service_->HandleNavigation(web_contents(), handle->GetPageTransition());
 
   input_tracker_.Start(
       base::TimeDelta::FromSeconds(g_seconds_delay_after_navigation));
@@ -249,6 +235,17 @@ void SiteEngagementService::Helper::WasHidden() {
 }
 
 // static
+void SiteEngagementService::Helper::CreateForWebContents(
+    content::WebContents* web_contents,
+    SiteEngagementService* service) {
+  DCHECK(web_contents);
+  if (!FromWebContents(web_contents)) {
+    web_contents->SetUserData(UserDataKey(), new SiteEngagementService::Helper(
+                                                 web_contents, service));
+  }
+}
+
+// static
 void SiteEngagementService::Helper::SetSecondsBetweenUserInputCheck(
     int seconds) {
   g_seconds_to_pause_engagement_detection = seconds;