Only use SupervisedUserNavigationObserver for child accounts.

This CL makes sure that SupervisedUserNavigationObserver is
created only for supervised user accounts. This saves memory
and processing time.

Bug: 1043232
Change-Id: I5d13ce0261d07c29384f5ba5dc83e420ed3138dd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2008315Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Dan S <danan@chromium.org>
Commit-Queue: Yilkal Abe <yilkal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733750}

chrome/browser/supervised_user/supervised_user_navigation_observer.cc

@@ -38,6 +38,22 @@ bool IsMainFrame(content::RenderFrameHost* render_frame_host) {
 
 using content::NavigationEntry;
 
+// static
+void SupervisedUserNavigationObserver::MaybeCreateForWebContents(
+    content::WebContents* web_contents) {
+  DCHECK(web_contents);
+  Profile* user_profile =
+      Profile::FromBrowserContext(web_contents->GetBrowserContext());
+  if (!user_profile->IsSupervised())
+    return;
+
+  if (!FromWebContents(web_contents)) {
+    web_contents->SetUserData(
+        UserDataKey(),
+        base::WrapUnique(new SupervisedUserNavigationObserver(web_contents)));
+  }
+}
+
 SupervisedUserNavigationObserver::~SupervisedUserNavigationObserver() {
   supervised_user_service_->RemoveObserver(this);
 }

chrome/browser/supervised_user/supervised_user_navigation_observer.h

@@ -35,6 +35,10 @@ class SupervisedUserNavigationObserver
       public SupervisedUserServiceObserver,
       public supervised_user::mojom::SupervisedUserCommands {
  public:
+  // Creates SupervisedUserNavigationObserver if the profile is a child user.
+  static void MaybeCreateForWebContents(content::WebContents* web_contents);
+  static void CreateForWebContents(content::WebContents* web_contents) = delete;
+
   ~SupervisedUserNavigationObserver() override;
 
   const std::vector<std::unique_ptr<const sessions::SerializedNavigationEntry>>&

chrome/browser/ui/tab_helpers.cc

@@ -372,7 +372,7 @@ void TabHelpers::AttachTabHelpers(WebContents* web_contents) {
 #endif
 
 #if BUILDFLAG(ENABLE_SUPERVISED_USERS)
-  SupervisedUserNavigationObserver::CreateForWebContents(web_contents);
+  SupervisedUserNavigationObserver::MaybeCreateForWebContents(web_contents);
 #endif
 
   if (predictors::LoadingPredictorFactory::GetForProfile(profile))