Update from chromium https://crrev.com/304586

base/files/file_util.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 "base/files/file_util.h"
 
 #if defined(OS_WIN)
 #include <io.h>
 #endif
 #include <stdio.h>
@@ skipping 29 matching lines @@
     running_size += file_iter.GetInfo().GetSize();
   return running_size;
 }
 
 bool Move(const FilePath& from_path, const FilePath& to_path) {
   if (from_path.ReferencesParent() || to_path.ReferencesParent())
     return false;
   return internal::MoveUnsafe(from_path, to_path);
 }
 
-bool CopyFile(const FilePath& from_path, const FilePath& to_path) {
-  if (from_path.ReferencesParent() || to_path.ReferencesParent())
-    return false;
-  return internal::CopyFileUnsafe(from_path, to_path);
-}
-
 bool ContentsEqual(const FilePath& filename1, const FilePath& filename2) {
   // We open the file in binary format even if they are text files because
   // we are just comparing that bytes are exactly same in both files and not
   // doing anything smart with text formatting.
   std::ifstream file1(filename1.value().c_str(),
                       std::ios::in | std::ios::binary);
   std::ifstream file2(filename2.value().c_str(),
                       std::ios::in | std::ios::binary);
 
   // Even if both files aren't openable (and thus, in some sense, "equal"),
@@ skipping 186 matching lines @@
     if (!PathExists(new_path) &&
         (!have_suffix || !PathExists(FilePath(new_path.value() + suffix)))) {
       return count;
     }
   }
 
   return -1;
 }
 
 }  // namespace base