In the past we also autofill into invisible <input> fields for the
following scenario:
frame1:
<input id="visibile-cc-number"/>
<input id="invisibile-cc-name"/>
<input id="invisibile-cc-exp"/>
frame2:
<input id="invisibile-cc-number"/>
<input id="visibile-cc-name"/>
<input id="invisibile-cc-exp"/>
frame3:
<input id="invisibile-cc-number"/>
<input id="invisibile-cc-name"/>
<input id="visibile-cc-exp"/>
So when autofilling the first frame, we also autofill invisible fields in
the same frame - cc-name and cc-exp, and then the website propagates these
values to other frames. Although this behavior results in the correct autofill
for all visible <input> across different frames, it can cause issues with display
highlights, clearing autofill results.
Now that we have implemented support for autofill across iframes, we should no
longer autofill into invisible fields.
Differential Revision: https://phabricator.services.mozilla.com/D223294
ab6314344b