Get base_unittests building with the macOS 10.13.0 SDK

base/mac/scoped_objc_class_swizzler_unittest.mm

Index: base/mac/scoped_objc_class_swizzler_unittest.mm
diff --git a/base/mac/scoped_objc_class_swizzler_unittest.mm b/base/mac/scoped_objc_class_swizzler_unittest.mm
index eacd10518218edfbcafa3370cf9f3a547cdefa82..79820a3ffa5fb8e79a6d9aacf3ca76bb8c31740d 100644
--- a/base/mac/scoped_objc_class_swizzler_unittest.mm
+++ b/base/mac/scoped_objc_class_swizzler_unittest.mm
@@ -115,7 +115,8 @@ TEST(ObjCClassSwizzlerTest, SwizzleClassMethods) {
 
     IMP original = swizzler.GetOriginalImplementation();
     id expected_result = reinterpret_cast<id>(10);
-    EXPECT_EQ(expected_result, original(nil, @selector(function)));
+    EXPECT_EQ(expected_result,
+              original([ObjCClassSwizzlerTestOne class], @selector(function)));
   }
 
   EXPECT_EQ(10, [ObjCClassSwizzlerTestOne function]);