Convert //components/prefs from scoped_ptr to std::unique_ptr

components/prefs/pref_service_factory.h

Index: components/prefs/pref_service_factory.h
diff --git a/components/prefs/pref_service_factory.h b/components/prefs/pref_service_factory.h
index bf7f56ceec12a0aa1f70d6a853aaf57b66d07102..0427543b4606750d86e930ce37199e68dd95dc96 100644
--- a/components/prefs/pref_service_factory.h
+++ b/components/prefs/pref_service_factory.h
@@ -67,7 +67,7 @@ class COMPONENTS_PREFS_EXPORT PrefServiceFactory {
 
   // Creates a PrefService object initialized with the parameters from
   // this factory.
-  scoped_ptr<PrefService> Create(PrefRegistry* registry);
+  std::unique_ptr<PrefService> Create(PrefRegistry* registry);
 
  protected:
   scoped_refptr<PrefStore> managed_prefs_;