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

chrome/browser/chromeos/login/wallpaper_manager_browsertest.cc

Index: chrome/browser/chromeos/login/wallpaper_manager_browsertest.cc
diff --git a/chrome/browser/chromeos/login/wallpaper_manager_browsertest.cc b/chrome/browser/chromeos/login/wallpaper_manager_browsertest.cc
index 77833c019dcb58b8c25998d246553dfdb90c9cae..0a5b626246d6265ca1d3d0f697564670a6e6283b 100644
--- a/chrome/browser/chromeos/login/wallpaper_manager_browsertest.cc
+++ b/chrome/browser/chromeos/login/wallpaper_manager_browsertest.cc
@@ -94,7 +94,7 @@ class WallpaperManagerBrowserTest : public CrosInProcessBrowserTest,
                                         const std::string& id) {
     base::FilePath wallpaper_path =
         WallpaperManager::Get()->GetCustomWallpaperPath(sub_dir, email, id);
-    if (!file_util::DirectoryExists(wallpaper_path.DirName()))
+    if (!base::DirectoryExists(wallpaper_path.DirName()))
       file_util::CreateDirectory(wallpaper_path.DirName());
 
     return wallpaper_path;