Chrome-parity navigation work for the PDF viewer:
- Find in document (ctrl-f): query editor, match counter, Enter/Shift+Enter
and ctrl-g navigation, yellow highlights with a stronger tint on the
active match, and a page jump per match.
- Internal link destinations: pdfium now reports dest_page for GoTo links,
so clicking a link that points inside the document jumps to that page
instead of being dropped.
- Space/Shift+Space scroll the viewport a screen at a time, unless the
find bar has focus so the query stays typeable.