Fix UNSAFE_TODO() in BC_OnedCode128Writer_unittest.cpp.

Apply first() to a deduced span rather than using two-arg constructor.

Change-Id: Id9882b0f0ed03bdc406a7e1851907468609343bd
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/133292
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
diff --git a/fxbarcode/oned/BC_OnedCode128Writer_unittest.cpp b/fxbarcode/oned/BC_OnedCode128Writer_unittest.cpp
index 7905093..1d2a197 100644
--- a/fxbarcode/oned/BC_OnedCode128Writer_unittest.cpp
+++ b/fxbarcode/oned/BC_OnedCode128Writer_unittest.cpp
@@ -6,7 +6,6 @@
 
 #include <iterator>
 
-#include "core/fxcrt/compiler_specific.h"
 #include "core/fxcrt/span.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -17,7 +16,7 @@
 
 struct TestCase {
   pdfium::span<const int32_t> pattern_span() const {
-    return UNSAFE_TODO(pdfium::span(patterns, num_patterns));
+    return pdfium::span(patterns).first(num_patterns);
   }
 
   const char* input;