[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, 2 insertions, 8 deletions

diff --git a/platform/ios/src/MGLMapView.mm b/platform/ios/src/MGLMapView.mm
index a4f994a2f4..fa49a2f280 100644
--- a/platform/ios/src/MGLMapView.mm
+++ b/platform/ios/src/MGLMapView.mm
@@ -10,7 +10,6 @@
 #include <mbgl/map/mode.hpp>
 #include <mbgl/util/platform.hpp>
 #include <mbgl/storage/reachability.h>
-#include <mbgl/util/default_thread_pool.hpp>
 #include <mbgl/storage/resource_options.hpp>
 #include <mbgl/storage/network_status.hpp>
 #include <mbgl/style/style.hpp>
@@ -29,7 +28,6 @@
 #include <mbgl/util/default_styles.hpp>
 #include <mbgl/util/chrono.hpp>
 #include <mbgl/util/run_loop.hpp>
-#include <mbgl/util/shared_thread_pool.hpp>
 #include <mbgl/util/string.hpp>
 #include <mbgl/util/projection.hpp>
 
@@ -280,8 +278,6 @@ public:
     MBGLView *_mbglView;
     std::unique_ptr<MGLRenderFrontend> _rendererFrontend;
     
-    std::shared_ptr<mbgl::ThreadPool> _mbglThreadPool;
-
     BOOL _opaque;
 
     MGLAnnotationTagContextMap _annotationContextsByAnnotationTag;
@@ -476,9 +472,8 @@ public:
 
     // setup mbgl map
     MGLRendererConfiguration *config = [MGLRendererConfiguration currentConfiguration];
-    _mbglThreadPool = mbgl::sharedThreadPool();
 
-    auto renderer = std::make_unique<mbgl::Renderer>(*_mbglView, config.scaleFactor, *_mbglThreadPool, config.cacheDir, config.localFontFamilyName);
+    auto renderer = std::make_unique<mbgl::Renderer>(*_mbglView, config.scaleFactor, config.cacheDir, config.localFontFamilyName);
     BOOL enableCrossSourceCollisions = !config.perSourceCollisions;
     _rendererFrontend = std::make_unique<MGLRenderFrontend>(std::move(renderer), self, *_mbglView);
 
@@ -495,7 +490,7 @@ public:
                    .withAssetPath([NSBundle mainBundle].resourceURL.path.UTF8String);
 
     NSAssert(!_mbglMap, @"_mbglMap should be NULL");
-    _mbglMap = new mbgl::Map(*_rendererFrontend, *_mbglView, *_mbglThreadPool, mapOptions, resourceOptions);
+    _mbglMap = new mbgl::Map(*_rendererFrontend, *_mbglView, mapOptions, resourceOptions);
 
     // start paused if in IB
     if (background) {
@@ -772,7 +767,6 @@ public:
     _mbglView = nullptr;
 
     _rendererFrontend.reset();
-    _mbglThreadPool.reset();
 }
 
 - (void)dealloc