Move WriteFile and WriteFileDescriptor from file_util to base namespace.

cloud_print/service/win/cloud_print_service_config.cc

Index: cloud_print/service/win/cloud_print_service_config.cc
diff --git a/cloud_print/service/win/cloud_print_service_config.cc b/cloud_print/service/win/cloud_print_service_config.cc
index 955682603dd1cfcf44120173f21e2a134a4d1b86..70f50c725f0aa7f2b835a0469477016bed70e2f1 100644
--- a/cloud_print/service/win/cloud_print_service_config.cc
+++ b/cloud_print/service/win/cloud_print_service_config.cc
@@ -389,7 +389,7 @@ void SetupDialog::Install(const base::string16& user,
   if (contents.empty())
     return ShowError(IDS_ERROR_FAILED_CREATE_CONFIG);
 
-  size_t written = file_util::WriteFile(file, contents.c_str(),
+  size_t written = base::WriteFile(file, contents.c_str(),
                                         contents.size());
   if (written != contents.size()) {
     DWORD last_error = GetLastError();