[ObjC ARC] Converts ios/chrome/browser/ui/settings:unit_tests to ARC.

ios/chrome/browser/ui/settings/sync_encryption_collection_view_controller_unittest.mm

Index: ios/chrome/browser/ui/settings/sync_encryption_collection_view_controller_unittest.mm
diff --git a/ios/chrome/browser/ui/settings/sync_encryption_collection_view_controller_unittest.mm b/ios/chrome/browser/ui/settings/sync_encryption_collection_view_controller_unittest.mm
index 47f94d889a100e19615bec9702afd506ca9826ba..08a13aa2d5bb7ee0cfa5e2bbb66597257d8234b6 100644
--- a/ios/chrome/browser/ui/settings/sync_encryption_collection_view_controller_unittest.mm
+++ b/ios/chrome/browser/ui/settings/sync_encryption_collection_view_controller_unittest.mm
@@ -22,6 +22,10 @@
 #import "testing/gtest_mac.h"
 #include "ui/base/l10n/l10n_util.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 
 using testing::NiceMock;
@@ -59,7 +63,7 @@ class SyncEncryptionCollectionViewControllerTest
     CreateController();
   }
 
-  CollectionViewController* NewController() override NS_RETURNS_RETAINED {
+  CollectionViewController* InstantiateController() override {
     return [[SyncEncryptionCollectionViewController alloc]
         initWithBrowserState:chrome_browser_state_.get()];
   }