Convert //ios from scoped_ptr to std::unique_ptr.

ios/chrome/browser/safe_browsing/safe_browsing_service.cc

Index: ios/chrome/browser/safe_browsing/safe_browsing_service.cc
diff --git a/ios/chrome/browser/safe_browsing/safe_browsing_service.cc b/ios/chrome/browser/safe_browsing/safe_browsing_service.cc
index e2bbe92aeb025c15144a60f4b7ff938b34f6f558..74c5b1c6bdf4382f8a03af313916990962117c33 100644
--- a/ios/chrome/browser/safe_browsing/safe_browsing_service.cc
+++ b/ios/chrome/browser/safe_browsing/safe_browsing_service.cc
@@ -90,9 +90,9 @@ class SafeBrowsingURLRequestContextGetter
 
   scoped_refptr<net::URLRequestContextGetter> system_context_getter_;
 
-  scoped_ptr<net::CookieStore> safe_browsing_cookie_store_;
+  std::unique_ptr<net::CookieStore> safe_browsing_cookie_store_;
 
-  scoped_ptr<net::URLRequestContext> safe_browsing_request_context_;
+  std::unique_ptr<net::URLRequestContext> safe_browsing_request_context_;
 
   scoped_refptr<base::SingleThreadTaskRunner> network_task_runner_;
 };
@@ -387,7 +387,7 @@ void SafeBrowsingService::RemovePrefService(PrefService* pref_service) {
   }
 }
 
-scoped_ptr<SafeBrowsingService::StateSubscription>
+std::unique_ptr<SafeBrowsingService::StateSubscription>
 SafeBrowsingService::RegisterStateCallback(
     const base::Callback<void(void)>& callback) {
   DCHECK_CURRENTLY_ON(web::WebThread::UI);