R1:c0efecb56194

Specify encoding in <meta>

Summary: Phabricator sends information about encoding in Content-Type header but
when I save the HTML page then this information is lost.

Test Plan: /

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, epriestley

Differential Revision: https://secure.phabricator.com/D1561