The content thumbnailers for each frontend were being provided the
contents url. This was only ever used to call the urldb thumbnail
setting API.
This changes it so the single callsite that passed a valid url adds
the bitmap to that url itself in desktop_history.c instead of forcing
every frontend to require the urldb API.
Additionally the old API could pass the url as NULL which was causing
asserts where this was not an expected parameter value. Because of
this this fixes bug #2286 which was also present in the monkey
frontend as both called nsurl_access() on the url without the NULL
check and caused an assertion.
The netsurf core is driven from numerous operation tables most of
which are now set through a common netsurf_register() interface. The
font and plotting interfaces are currently separate and unlike all the
other operation tables are modified for differing contexts.
This change moves the font operations alongside all the other
operations table and remove unnecessary interaction with the renderers
font internals. Further this also removes the need for css internals
to be visible in frontends.
