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

ios/chrome/browser/undo/bookmark_undo_service_factory.h

Index: ios/chrome/browser/undo/bookmark_undo_service_factory.h
diff --git a/ios/chrome/browser/undo/bookmark_undo_service_factory.h b/ios/chrome/browser/undo/bookmark_undo_service_factory.h
index cbd569cbf673480296d46d10d9c960159b9a6ec6..0427de409da4d87804f06fa59b0fa5107fd58983 100644
--- a/ios/chrome/browser/undo/bookmark_undo_service_factory.h
+++ b/ios/chrome/browser/undo/bookmark_undo_service_factory.h
@@ -5,8 +5,9 @@
 #ifndef IOS_CHROME_BROWSER_UNDO_BOOKMARK_UNDO_SERVICE_FACTORY_H_
 #define IOS_CHROME_BROWSER_UNDO_BOOKMARK_UNDO_SERVICE_FACTORY_H_
 
+#include <memory>
+
 #include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
 #include "components/keyed_service/ios/browser_state_keyed_service_factory.h"
 
 namespace base {
@@ -37,7 +38,7 @@ class BookmarkUndoServiceFactory : public BrowserStateKeyedServiceFactory {
   ~BookmarkUndoServiceFactory() override;
 
   // BrowserStateKeyedServiceFactory implementation.
-  scoped_ptr<KeyedService> BuildServiceInstanceFor(
+  std::unique_ptr<KeyedService> BuildServiceInstanceFor(
       web::BrowserState* context) const override;
 
   DISALLOW_COPY_AND_ASSIGN(BookmarkUndoServiceFactory);