Migrate the site engagement service to use DidFinishNavigation.

chrome/browser/engagement/site_engagement_helper.h

Index: chrome/browser/engagement/site_engagement_helper.h
diff --git a/chrome/browser/engagement/site_engagement_helper.h b/chrome/browser/engagement/site_engagement_helper.h
index 4a56fb0b7f09cb7000b3c9e6c2335657df2fe402..4a331af6c07c3064eaff7e146f64bbf9032961ad 100644
--- a/chrome/browser/engagement/site_engagement_helper.h
+++ b/chrome/browser/engagement/site_engagement_helper.h
@@ -12,6 +12,7 @@
 #include "content/public/browser/web_contents_user_data.h"
 
 namespace content {
+class NavigationHandle;
 class WebContents;
 }
 
@@ -153,9 +154,7 @@ class SiteEngagementHelper
   void RecordMediaPlaying(bool is_hidden);
 
   // content::WebContentsObserver overrides.
-  void DidNavigateMainFrame(
-      const content::LoadCommittedDetails& details,
-      const content::FrameNavigateParams& params) override;
+  void DidFinishNavigation(content::NavigationHandle* handle) override;
   void WasShown() override;
   void WasHidden() override;