Move WriteFile and WriteFileDescriptor from file_util to base namespace.

chrome/browser/google/google_update_settings_posix.cc

Index: chrome/browser/google/google_update_settings_posix.cc
diff --git a/chrome/browser/google/google_update_settings_posix.cc b/chrome/browser/google/google_update_settings_posix.cc
index b8615769aaba79593fd420138752572763cb04cf..ac661922dbabb411c96d4aa28627e997093d3cd5 100644
--- a/chrome/browser/google/google_update_settings_posix.cc
+++ b/chrome/browser/google/google_update_settings_posix.cc
@@ -48,7 +48,7 @@ bool GoogleUpdateSettings::SetCollectStatsConsent(bool consented) {
          !google_update::posix_guid().empty())) {
       const char* c_str = google_update::posix_guid().c_str();
       int size = google_update::posix_guid().size();
-      return file_util::WriteFile(consent_file, c_str, size) == size;
+      return base::WriteFile(consent_file, c_str, size) == size;
     }
   } else {
     google_update::posix_guid().clear();