Use DOMError.name instead of deprecated FileError.code for handling file errors.

On the way also remove internal API that depends on FileError.code for consistency.

BUG=277949

Review URL: https://codereview.chromium.org/144713004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247205 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247205