Move WriteFile and WriteFileDescriptor from file_util to base namespace.

chrome/test/chromedriver/util.cc

Index: chrome/test/chromedriver/util.cc
diff --git a/chrome/test/chromedriver/util.cc b/chrome/test/chromedriver/util.cc
index 39dd768c0d3835edb475ebb10530d03dbcb8e440..f1fac342f262812a6b9b9dfffae579851ac64844 100644
--- a/chrome/test/chromedriver/util.cc
+++ b/chrome/test/chromedriver/util.cc
@@ -90,7 +90,7 @@ Status UnzipArchive(const base::FilePath& unzip_dir,
 
   base::FilePath archive = dir.path().AppendASCII("temp.zip");
   int length = bytes.length();
-  if (file_util::WriteFile(archive, bytes.c_str(), length) != length)
+  if (base::WriteFile(archive, bytes.c_str(), length) != length)
     return Status(kUnknownError, "could not write file to temp dir");
 
   if (!zip::Unzip(archive, unzip_dir))