diff -r 000000000000 -r 6474c204b198 security/sandbox/chromium/base/strings/string_util_stripped.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/security/sandbox/chromium/base/strings/string_util_stripped.cc	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,41 @@
+#include <wchar.h>
+
+namespace base {
+
+bool IsWprintfFormatPortable(const wchar_t* format) {
+  for (const wchar_t* position = format; *position != '\0'; ++position) {
+    if (*position == '%') {
+      bool in_specification = true;
+      bool modifier_l = false;
+      while (in_specification) {
+        // Eat up characters until reaching a known specifier.
+        if (*++position == '\0') {
+          // The format string ended in the middle of a specification.  Call
+          // it portable because no unportable specifications were found.  The
+          // string is equally broken on all platforms.
+          return true;
+        }
+
+        if (*position == 'l') {
+          // 'l' is the only thing that can save the 's' and 'c' specifiers.
+          modifier_l = true;
+        } else if (((*position == 's' || *position == 'c') && !modifier_l) ||
+                   *position == 'S' || *position == 'C' || *position == 'F' ||
+                   *position == 'D' || *position == 'O' || *position == 'U') {
+          // Not portable.
+          return false;
+        }
+
+        if (wcschr(L"diouxXeEfgGaAcspn%", *position)) {
+          // Portable, keep scanning the rest of the format string.
+          in_specification = false;
+        }
+      }
+    }
+  }
+
+  return true;
+}
+
+}  // namespace base
+