Move WriteFile and WriteFileDescriptor from file_util to base namespace.

chrome/utility/image_writer/image_writer_unittest.cc

Index: chrome/utility/image_writer/image_writer_unittest.cc
diff --git a/chrome/utility/image_writer/image_writer_unittest.cc b/chrome/utility/image_writer/image_writer_unittest.cc
index bb7f31b9c689e02d66b6a71dc95dc8f996377767..0673e00ed56d46c0a2900654bda591434ae0e2da 100644
--- a/chrome/utility/image_writer/image_writer_unittest.cc
+++ b/chrome/utility/image_writer/image_writer_unittest.cc
@@ -38,7 +38,7 @@ class ImageWriterUtilityTest : public testing::Test {
     scoped_ptr<char[]> buffer(new char[kTestFileSize]);
     memset(buffer.get(), pattern, kTestFileSize);
 
-    ASSERT_TRUE(file_util::WriteFile(path, buffer.get(), kTestFileSize));
+    ASSERT_TRUE(base::WriteFile(path, buffer.get(), kTestFileSize));
   }
 
   void FillDefault(const base::FilePath& path) { FillFile(path, kTestPattern); }