Updated mediawiki/extensions
Project: mediawiki/extensions/Flow  4edd7b00d5d94b1849b4f5449c17c897c970cc1a

Hygiene: Only create DOMDocument once in ContentFixer

It seems inefficient for each ContentFixer implementation to create and
destroy its own DOMDocument. This patch consolidates that into the
parsoid Controller.

Change-Id: I8f7a4b8ee730acb80b2283812a4859282d79aaaf