Most of the ReaderMode.jsm and Readability.js code is only needed when we
actually need to render a document in reader mode, but also winds up loaded
into any process where we ever check if a page is readerable. This winds up
wasting a huge amount of memory (and probably a huge amount of CPU time)
loading code which is almost never used.
This patch splits ReaderMode.jsm into two modules, one for checking
readability, one for actually entering reader mode. It also separates out the
isProbablyReaderable checks from Readability.js, since the overhead of loading
that script before it's needed is unsupportable.
This means we're probably going to need some effort to keep Readerable.jsm and
Readability.js in sync, but the code in question is pretty trivial, so it
shouldn't be too difficult.
Differential Revision: https://phabricator.services.mozilla.com/D3687
--HG--
rename : toolkit/components/reader/Readability.js => toolkit/components/reader/Readability-readerable.js
rename : toolkit/components/reader/ReaderMode.jsm => toolkit/components/reader/Readerable.js
extra : rebase_source : 66712057591ae20dd66234e3dc78fbba90a6914e
extra : amend_source : f908f62f49ea54b9099ddb87d9f2fc11f12d4dee
22d4bb0074