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

ui/shell_dialogs/select_file_dialog_mac.mm

 // 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 "ui/shell_dialogs/select_file_dialog.h"
 
 #import <Cocoa/Cocoa.h>
 #include <CoreServices/CoreServices.h>
 
 #include <map>
@@ skipping 182 matching lines @@
 
   if (!title.empty())
     [dialog setTitle:base::SysUTF16ToNSString(title)];
 
   NSString* default_dir = nil;
   NSString* default_filename = nil;
   if (!default_path.empty()) {
     // The file dialog is going to do a ton of stats anyway. Not much
     // point in eliminating this one.
     base::ThreadRestrictions::ScopedAllowIO allow_io;
-    if (file_util::DirectoryExists(default_path)) {
+    if (base::DirectoryExists(default_path)) {
       default_dir = base::SysUTF8ToNSString(default_path.value());
     } else {
       default_dir = base::SysUTF8ToNSString(default_path.DirName().value());
       default_filename =
           base::SysUTF8ToNSString(default_path.BaseName().value());
     }
   }
 
   NSArray* allowed_file_types = nil;
   if (file_types) {
@@ skipping 203 matching lines @@
 
 namespace ui {
 
 SelectFileDialog* CreateMacSelectFileDialog(
     SelectFileDialog::Listener* listener,
     SelectFilePolicy* policy) {
   return new SelectFileDialogImpl(listener, policy);
 }
 
 }  // namespace ui