[ObjC ARC] Converts ios/web:ios_web_web_state_ui_unittests to ARC.

ios/web/web_state/ui/wk_back_forward_list_item_holder_unittest.mm

Index: ios/web/web_state/ui/wk_back_forward_list_item_holder_unittest.mm
diff --git a/ios/web/web_state/ui/wk_back_forward_list_item_holder_unittest.mm b/ios/web/web_state/ui/wk_back_forward_list_item_holder_unittest.mm
index 5d31e245737b31db9132a6c4c2c9afb4ea00fe16..48c1465748828d59309027bd191c8dd0eafea322 100644
--- a/ios/web/web_state/ui/wk_back_forward_list_item_holder_unittest.mm
+++ b/ios/web/web_state/ui/wk_back_forward_list_item_holder_unittest.mm
@@ -12,6 +12,10 @@
 #import "testing/gtest_mac.h"
 #include "testing/platform_test.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 
 // Test fixture for WKBackForwardListItemHolder class.
@@ -50,11 +54,11 @@ TEST_F(WKBackForwardListItemHolderTest, GetHolderFromDifferentNavigationItem) {
 // directly and will crash.
 TEST_F(WKBackForwardListItemHolderTest, GetBackForwardListItemFromHolder) {
   std::unique_ptr<web::NavigationItem> item(NavigationItem::Create());
-  base::scoped_nsobject<NSObject> input([[NSObject alloc] init]);
+  NSObject* input = [[NSObject alloc] init];
   WKBackForwardListItemHolder* holder =
       WKBackForwardListItemHolder::FromNavigationItem(item.get());
   holder->set_back_forward_list_item(
-      static_cast<WKBackForwardListItem*>(input.get()));
+      static_cast<WKBackForwardListItem*>(input));
   NSObject* result = holder->back_forward_list_item();
   EXPECT_EQ(input, result);
 }
@@ -102,28 +106,4 @@ TEST_F(WKBackForwardListItemHolderTest, GetNavigationTypeFromHolder) {
   EXPECT_EQ(type, holder->navigation_type());
 }
 
-// Tests that |back_forward_list_item| returns nil if the internal
-// WKBackForwardListItem was deallocated. The test bellow uses NSObject
-// instead of WKBackForwardListItem because WKBackForwardListItem alloc/
-// release is not designed to be called directly and will crash.
-TEST_F(WKBackForwardListItemHolderTest, GetNilBackForwardListItemFromHolder) {
-  std::unique_ptr<web::NavigationItem> item(NavigationItem::Create());
-  WKBackForwardListItemHolder* holder =
-      WKBackForwardListItemHolder::FromNavigationItem(item.get());
-
-  // Add a WKBackForwardListItem and verify that |back_forward_list_item|
-  // returns does not return nil.
-  base::scoped_nsobject<NSObject> input([[NSObject alloc] init]);
-  holder->set_back_forward_list_item(
-      static_cast<WKBackForwardListItem*>(input.get()));
-  NSObject* result = holder->back_forward_list_item();
-  EXPECT_NE(nil, result);
-
-  // Deallocate the WKBackForwardListItem and verify that
-  // |back_forward_list_item| returns nil.
-  input.reset();
-  result = holder->back_forward_list_item();
-  EXPECT_EQ(nil, result);
-}
-
 }  // namespace web