Move WriteFile and WriteFileDescriptor from file_util to base namespace.

chrome/test/base/ui_test_utils.cc

Index: chrome/test/base/ui_test_utils.cc
diff --git a/chrome/test/base/ui_test_utils.cc b/chrome/test/base/ui_test_utils.cc
index 02cab8445a37401ad28d75cabf79c99d42a7153e..e682a43880679c106f41a8e8a59047e5e8dc5045 100644
--- a/chrome/test/base/ui_test_utils.cc
+++ b/chrome/test/base/ui_test_utils.cc
@@ -487,7 +487,7 @@ bool SaveScreenSnapshotToDirectory(const base::FilePath& directory,
     if (ui::GrabDesktopSnapshot(bounds, &png_data) &&
         png_data.size() <= INT_MAX) {
       int bytes = static_cast<int>(png_data.size());
-      int written = file_util::WriteFile(
+      int written = base::WriteFile(
           out_path, reinterpret_cast<char*>(&png_data[0]), bytes);
       succeeded = (written == bytes);
     }