Implement IsNonNativeLocalPathDirectory for supporting non-local non-Drive directory access in apps.

chrome/browser/chromeos/drive/file_system_util.h

Index: chrome/browser/chromeos/drive/file_system_util.h
diff --git a/chrome/browser/chromeos/drive/file_system_util.h b/chrome/browser/chromeos/drive/file_system_util.h
index 278ecbc88790e6860a1b4cdd225ad46fea6c1c85..a16ed6046f5ea3969a8accf98fc1e59c8f4b1a7a 100644
--- a/chrome/browser/chromeos/drive/file_system_util.h
+++ b/chrome/browser/chromeos/drive/file_system_util.h
@@ -144,12 +144,6 @@ void PrepareWritableFileAndRun(Profile* profile,
                                const base::FilePath& path,
                                const PrepareWritableFileCallback& callback);
 
-// Checks whether a directory exists at the given Drive path |directory|.
-// Must be called from UI thread. The result will be called back to |callback|.
-void CheckDirectoryExists(Profile* profile,
-                          const base::FilePath& directory,
-                          const FileOperationCallback& callback);
-
 // Ensures the existence of |directory| of '/special/drive/foo'.  This will
 // create |directory| and its ancestors if they don't exist.  |callback| is
 // invoked after making sure that |directory| exists.  |callback| should