Move PathIsWritable, DirectoryExists, ContentsEqual, and TextContentsEqual to the base namespace.

chrome/browser/extensions/api/file_system/file_system_api.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 "chrome/browser/extensions/api/file_system/file_system_api.h"
 
 #include "apps/saved_files_service.h"
 #include "apps/shell_window.h"
 #include "base/bind.h"
 #include "base/file_util.h"
@@ skipping 640 matching lines @@
   // smoothly, all accessed paths need to be registered in the list of
   // external mount points.
   fileapi::ExternalMountPoints::GetSystemInstance()->RegisterFileSystem(
       name, fileapi::kFileSystemTypeNativeLocal, path);
 }
 
 void FileSystemChooseEntryFunction::SetInitialPathOnFileThread(
     const base::FilePath& suggested_name,
     const base::FilePath& previous_path) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
-  if (!previous_path.empty() && file_util::DirectoryExists(previous_path)) {
+  if (!previous_path.empty() && base::DirectoryExists(previous_path)) {
     initial_path_ = previous_path.Append(suggested_name);
   } else {
     base::FilePath documents_dir;
     if (PathService::Get(chrome::DIR_USER_DOCUMENTS, &documents_dir)) {
       initial_path_ = documents_dir.Append(suggested_name);
     } else {
       initial_path_ = suggested_name;
     }
   }
 }
@@ skipping 200 matching lines @@
     // ID that was passed to restoreEntry.
     RegisterFileSystemAndSendResponseWithIdOverride(
         file_entry->path,
         file_entry->writable ? WRITABLE : READ_ONLY,
         file_entry->id);
   }
   return true;
 }
 
 }  // namespace extensions