Move WriteFile and WriteFileDescriptor from file_util to base namespace.

chrome/tools/safe_browsing/sb_sigutil.cc

Index: chrome/tools/safe_browsing/sb_sigutil.cc
diff --git a/chrome/tools/safe_browsing/sb_sigutil.cc b/chrome/tools/safe_browsing/sb_sigutil.cc
index 4a6d9db1f350e0d62bf6084564ea18f03edfd04e..4d2f75bf951617d75389df7aa49c70cdf31a4a58 100644
--- a/chrome/tools/safe_browsing/sb_sigutil.cc
+++ b/chrome/tools/safe_browsing/sb_sigutil.cc
@@ -44,7 +44,7 @@ int main(int argc, char* argv[]) {
                            &signature_info);
 
   std::string serialized_info = signature_info.SerializeAsString();
-  int bytes_written = file_util::WriteFile(
+  int bytes_written = base::WriteFile(
       cmd_line->GetSwitchValuePath(kOutputFile),
       serialized_info.data(),
       serialized_info.size());