[core] Make the BackgroundScheduler a singleton

- Do not carry it over everywhere as parameter, it is a shared
  instance anyway and the lifecycle is pretty much the app lifecycle
  from the moment we instantiate a map.
- Rename to BackgroundScheduler because it is a Scheduler that will
  do tasks in the background, we don't make assumptions if it is a
  thread pool or a single thread.
- Most importantly, remove the dependency from `core` on `platform`.

2 files changed, 2 insertions, 2 deletions

diff --git a/test/src/mbgl/test/map_adapter.hpp b/test/src/mbgl/test/map_adapter.hpp
index 5bdab1d164..d4af579ae1 100644
--- a/test/src/mbgl/test/map_adapter.hpp
+++ b/test/src/mbgl/test/map_adapter.hpp
@@ -13,9 +13,8 @@ public:
     explicit MapAdapter(RendererFrontend& frontend,
                         MapObserver& observer,
                         std::shared_ptr<FileSource> fileSource,
-                        Scheduler& scheduler,
                         const MapOptions& options)
-        : Map(std::make_unique<Map::Impl>(frontend, observer, scheduler, std::move(fileSource), options)) {}
+        : Map(std::make_unique<Map::Impl>(frontend, observer, std::move(fileSource), options)) {}
 };
 
 } // namespace mbgl
diff --git a/test/src/mbgl/test/test.cpp b/test/src/mbgl/test/test.cpp
index 4c3dad1727..1c77aae2a1 100644
--- a/test/src/mbgl/test/test.cpp
+++ b/test/src/mbgl/test/test.cpp
@@ -1,3 +1,4 @@
+#include <mbgl/actor/scheduler.hpp>
 #include <mbgl/test.hpp>
 #include <mbgl/test/util.hpp>