Layers are added and removed dynamically on the Map thread when we use shape
annotations and we are iterating style.layers on the Worker thread without
any lock.
Now when we create a [Live|Vector]TileData at the Map thread we give it
a layers list (instead of the Style) and [Live|Vector]TileData will ultimately
make a copy of this list (on the Map thread, so no concurrency with
adding shape annotations).
The copy should be relatively cheap because we are using a shared pointer
for storing the layers on the list.
After parsing a tile, it redoes placement for that tile if the angle has
changed since it started parsing. These redo calls were accidentally
done from the worker thread. Assigning the new work to `workRequest`
caused it to cancel itself.
Fix the problem by calling redoPlacement from the map thread.
Also add a virtual setState() method to give subclasses a chance
to intercept the change of state. This will be used by VectorTileData
to release resources when the TileData becomes immutable.
We are also removing the code that is passing the Environment around
and instead, we get now the Environment in the TileData using
Environment::Get().
When processing the job, the work will be temporally registered to
the Environment as "TileWorker_0/0/0" which can be used for logging
in the future. At the end of the job, it gets unregistered
automatically from the Environment.
