Move WriteFile and WriteFileDescriptor from file_util to base namespace.

ash/desktop_background/desktop_background_controller_unittest.cc

 // Copyright (c) 2012 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.
 
 #include "ash/desktop_background/desktop_background_controller.h"
 
 #include <cmath>
 #include <cstdlib>
 
 #include "ash/ash_switches.h"
@@ skipping 197 matching lines @@
     const int kQuality = 80;
     std::vector<unsigned char> output;
     if (!gfx::JPEGCodec::Encode(
             static_cast<const unsigned char*>(bitmap.getPixels()),
             gfx::JPEGCodec::FORMAT_SkBitmap, width, height, bitmap.rowBytes(),
             kQuality, &output)) {
       LOG(ERROR) << "Unable to encode " << width << "x" << height << " bitmap";
       return false;
     }
 
-    size_t bytes_written = file_util::WriteFile(
+    size_t bytes_written = base::WriteFile(
         path, reinterpret_cast<const char*>(&output[0]), output.size());
     if (bytes_written != output.size()) {
       LOG(ERROR) << "Wrote " << bytes_written << " byte(s) instead of "
                  << output.size() << " to " << path.value();
       return false;
     }
 
     return true;
   }
 
@@ skipping 458 matching lines @@
   // new load task was started (since the previous one was interrupted by
   // SetCustomWallpaper()). See http://crbug.com/327443.
   TestObserver observer(controller_);
   ASSERT_TRUE(controller_->SetDefaultWallpaper(false));
   observer.WaitForWallpaperDataChanged();
   EXPECT_TRUE(ImageIsNearColor(controller_->GetWallpaper(),
                                kSmallWallpaperColor));
 }
 
 }  // namespace ash