Move WriteFile and WriteFileDescriptor from file_util to base namespace.

chrome/browser/first_run/first_run.cc

Index: chrome/browser/first_run/first_run.cc
diff --git a/chrome/browser/first_run/first_run.cc b/chrome/browser/first_run/first_run.cc
index a5e826d53e112018c7279f4ac804313585636ac9..d89e76bc1a885bca839be11427fc51a036212e10 100644
--- a/chrome/browser/first_run/first_run.cc
+++ b/chrome/browser/first_run/first_run.cc
@@ -568,7 +568,7 @@ bool CreateSentinel() {
   base::FilePath first_run_sentinel;
   if (!internal::GetFirstRunSentinelFilePath(&first_run_sentinel))
     return false;
-  return file_util::WriteFile(first_run_sentinel, "", 0) != -1;
+  return base::WriteFile(first_run_sentinel, "", 0) != -1;
 }
 
 // -- Platform-specific functions --