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

ios/chrome/browser/favicon/ios_chrome_large_icon_cache_factory.cc

Index: ios/chrome/browser/favicon/ios_chrome_large_icon_cache_factory.cc
diff --git a/ios/chrome/browser/favicon/ios_chrome_large_icon_cache_factory.cc b/ios/chrome/browser/favicon/ios_chrome_large_icon_cache_factory.cc
index 6b2627a8c94e455e5a620593a1d5236806935607..13b191c4b10ab7d02c893aa33b3cbef085438a26 100644
--- a/ios/chrome/browser/favicon/ios_chrome_large_icon_cache_factory.cc
+++ b/ios/chrome/browser/favicon/ios_chrome_large_icon_cache_factory.cc
@@ -4,6 +4,7 @@
 
 #include "ios/chrome/browser/favicon/ios_chrome_large_icon_cache_factory.h"
 
+#include "base/memory/ptr_util.h"
 #include "base/memory/singleton.h"
 #include "components/keyed_service/ios/browser_state_dependency_manager.h"
 #include "ios/chrome/browser/browser_state/browser_state_otr_helper.h"
@@ -29,10 +30,10 @@ IOSChromeLargeIconCacheFactory::IOSChromeLargeIconCacheFactory()
 
 IOSChromeLargeIconCacheFactory::~IOSChromeLargeIconCacheFactory() {}
 
-scoped_ptr<KeyedService>
+std::unique_ptr<KeyedService>
 IOSChromeLargeIconCacheFactory::BuildServiceInstanceFor(
     web::BrowserState* context) const {
-  return make_scoped_ptr(new LargeIconCache);
+  return base::WrapUnique(new LargeIconCache);
 }
 
 web::BrowserState* IOSChromeLargeIconCacheFactory::GetBrowserStateToUse(