Move WriteFile and WriteFileDescriptor from file_util to base namespace.

third_party/zlib/google/zip_reader.cc

Index: third_party/zlib/google/zip_reader.cc
diff --git a/third_party/zlib/google/zip_reader.cc b/third_party/zlib/google/zip_reader.cc
index 5bcc264702f5a959f5dd4ff178ba21cc973d545a..915dbbc79d149488c7f8946b490b4e1c77c9dc00 100644
--- a/third_party/zlib/google/zip_reader.cc
+++ b/third_party/zlib/google/zip_reader.cc
@@ -333,7 +333,7 @@ bool ZipReader::ExtractCurrentEntryToFd(const int fd) {
     } else if (num_bytes_read > 0) {
       // Some data is read. Write it to the output file descriptor.
       if (num_bytes_read !=
-          file_util::WriteFileDescriptor(fd, buf, num_bytes_read)) {
+          base::WriteFileDescriptor(fd, buf, num_bytes_read)) {
         success = false;
         break;
       }