Remove text encoding UI

Text encoding UI is removed as a part of the project Eraser effort.
Manual encoding selection is not necessary any more as the new
encoding detector is turned on by default.

Request for manual encoding switching which may still exist
can be met by utilizing Chrome extension. See the bug for
detailed discussion.

Also removed the default encoding in Settings -> Customize fonts ->
Fonts and encoding.

Discussion at chrome-ui-review can be found here


Cr-Commit-Position: refs/heads/master@{#415497}
48 files changed