When saving from the game's control panel, we use the thumbnail that was
created before the control panel opened. But when using the ScummVM
menu, we need to generate the thumbnail as usual. Otherwise, there may
not be any thumbnail at all, causing the save to fail.
The autosave refactoring that was done in
7adad5aaf5 used g_engine for identifying the
autosave slot. This worked for in-game save/load, but doesn't fit when
called from the launcher.
Fix by passing MetaEngine to SaveStateDescriptor ctor and using it for this
query.
Amends 7adad5aaf5.
Some engines call setAutosave and some don't. isAutosave is used to
determine if a saved game is an autosave, but in fact, on most cases it
just falls back to comparing the name to "Autosave".
This is wrong for several reasons:
* Older versions of ScummVM used Autosave 0.
* The name "Autosave" is translated, so if you change the language, it
won't be detected.
Instead of relying on the name, use the well-known getAutosaveSlot() from
Engine/MetaEngine.
Fixes#12735.
Torbjörn Andersson
Cameron Cawley
Eugene Sandulenko
Orgad Shaneh
SupSuper
Strangerke
Filippos Karapetis