[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`.

1 files changed, 1 insertions, 3 deletions

diff --git a/src/mbgl/style/sources/custom_geometry_source.cpp b/src/mbgl/style/sources/custom_geometry_source.cpp
index 7420be9320..6e9d8d65fb 100644
--- a/src/mbgl/style/sources/custom_geometry_source.cpp
+++ b/src/mbgl/style/sources/custom_geometry_source.cpp
@@ -4,7 +4,6 @@
 #include <mbgl/actor/actor.hpp>
 #include <mbgl/actor/scheduler.hpp>
 #include <mbgl/tile/tile_id.hpp>
-#include <mbgl/util/shared_thread_pool.hpp>
 #include <tuple>
 #include <map>
 
@@ -14,8 +13,7 @@ namespace style {
 CustomGeometrySource::CustomGeometrySource(std::string id,
                                        const CustomGeometrySource::Options options)
     : Source(makeMutable<CustomGeometrySource::Impl>(std::move(id), options)),
-    threadPool(sharedThreadPool()),
-    loader(std::make_unique<Actor<CustomTileLoader>>(*threadPool, options.fetchTileFunction, options.cancelTileFunction)) {
+    loader(std::make_unique<Actor<CustomTileLoader>>(Scheduler::GetBackground(), options.fetchTileFunction, options.cancelTileFunction)) {
 }
 
 CustomGeometrySource::~CustomGeometrySource() = default;