Revert 236252 "Update serial API."

> Update serial API.
> 
> BUG=155861,148741,140125,169555,171948,281908
> 
> Review URL: https://codereview.chromium.org/27246008

TBR=rockot@chromium.org

Review URL: https://codereview.chromium.org/79163002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236265 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236265