SupervisedUserNavigationThrottle: create only for supervised profiles

chrome/browser/supervised_user/supervised_user_navigation_throttle.cc

Index: chrome/browser/supervised_user/supervised_user_navigation_throttle.cc
diff --git a/chrome/browser/supervised_user/supervised_user_navigation_throttle.cc b/chrome/browser/supervised_user/supervised_user_navigation_throttle.cc
index ec74ae4619168776036806ad3ac4fee5cc00944f..b0e6c8fc9576b80f8e45326e6a403650d335e40e 100644
--- a/chrome/browser/supervised_user/supervised_user_navigation_throttle.cc
+++ b/chrome/browser/supervised_user/supervised_user_navigation_throttle.cc
@@ -122,6 +122,10 @@ SupervisedUserNavigationThrottle::MaybeCreateThrottleFor(
     content::NavigationHandle* navigation_handle) {
   if (!navigation_handle->IsInMainFrame())
     return nullptr;
+  Profile* profile = Profile::FromBrowserContext(
+      navigation_handle->GetWebContents()->GetBrowserContext());
+  if (!profile->IsSupervised())
+    return nullptr;
   // Can't use base::MakeUnique because the constructor is private.
   return base::WrapUnique(
       new SupervisedUserNavigationThrottle(navigation_handle));