Since we want to start collecting all form data through mapFrameTree on Fennec,
too, we need to change our filtering strategy for form data.
We can no longer bail out directly during the data collection loop and instead
have to filter the data after having collected all of it.

The easiest way to do that is to start using PrivacyFilter.filterFormData() on
Android as well.

MozReview-Commit-ID: GBos4Zn3l2U

--HG--
rename : browser/components/sessionstore/PrivacyFilter.jsm => toolkit/modules/sessionstore/PrivacyFilter.jsm
extra : rebase_source : 1c5dfce28716c82e3a237f6d559449cb904ae13a