Move WriteFile and WriteFileDescriptor from file_util to base namespace.

tools/imagediff/image_diff.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file input format is based loosely on
 // Tools/DumpRenderTree/ImageDiff.m
 
 // The exact format of this tool's output to stdout is important, to match
 // what the run-webkit-tests script expects.
 
@@ skipping 366 matching lines @@
 
   Image diff_image;
   bool same = CreateImageDiff(baseline_image, actual_image, &diff_image);
   if (same)
     return kStatusSame;
 
   std::vector<unsigned char> png_encoding;
   image_diff_png::EncodeRGBAPNG(
       diff_image.data(), diff_image.w(), diff_image.h(),
       diff_image.w() * 4, &png_encoding);
-  if (file_util::WriteFile(out_file,
+  if (base::WriteFile(out_file,
           reinterpret_cast<char*>(&png_encoding.front()),
           base::checked_cast<int>(png_encoding.size())) < 0)
     return kStatusError;
 
   return kStatusDifferent;
 }
 
 // It isn't strictly correct to only support ASCII paths, but this
 // program reads paths on stdin and the program that spawns it outputs
 // paths as non-wide strings anyway.
@@ skipping 42 matching lines @@
                         base::FilePath(args[2]));
     }
   } else if (args.size() == 2) {
     return CompareImages(
         base::FilePath(args[0]), base::FilePath(args[1]), histograms);
   }
 
   PrintHelp();
   return kStatusError;
 }