Make base compile with no "using base::FilePath".

base/file_util_posix.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/file_util.h"
 
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <fnmatch.h>
@@ skipping 40 matching lines @@
 #endif
 
 #if !defined(OS_IOS)
 #include <grp.h>
 #endif
 
 #if defined(OS_CHROMEOS)
 #include "base/chromeos/chromeos_version.h"
 #endif
 
+using base::FilePath;
+
 namespace file_util {
 
 namespace {
 
 #if defined(OS_BSD) || defined(OS_MACOSX)
 typedef struct stat stat_wrapper_t;
 static int CallStat(const char *path, stat_wrapper_t *sb) {
   base::ThreadRestrictions::AssertIOAllowed();
   return stat(path, sb);
 }
@@ skipping 1053 matching lines @@
 
     allowed_group_ids.insert(group_record->gr_gid);
   }
 
   return VerifyPathControlledByUser(
       kFileSystemRoot, path, kRootUid, allowed_group_ids);
 }
 #endif  // defined(OS_MACOSX) && !defined(OS_IOS)
 
 }  // namespace file_util