[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, 3 insertions, 7 deletions

diff --git a/test/style/style.test.cpp b/test/style/style.test.cpp
index 7f57651331..72f74d3b01 100644
--- a/test/style/style.test.cpp
+++ b/test/style/style.test.cpp
@@ -9,7 +9,6 @@
 #include <mbgl/style/layers/line_layer.hpp>
 #include <mbgl/util/io.hpp>
 #include <mbgl/util/run_loop.hpp>
-#include <mbgl/util/default_thread_pool.hpp>
 
 #include <memory>
 
@@ -19,9 +18,8 @@ using namespace mbgl::style;
 TEST(Style, Properties) {
     util::RunLoop loop;
 
-    ThreadPool threadPool{ 1 };
     StubFileSource fileSource;
-    Style::Impl style { threadPool, fileSource, 1.0 };
+    Style::Impl style { fileSource, 1.0 };
 
     style.loadJSON(R"STYLE({"name": "Test"})STYLE");
     ASSERT_EQ("Test", style.getName());
@@ -62,9 +60,8 @@ TEST(Style, Properties) {
 TEST(Style, DuplicateSource) {
     util::RunLoop loop;
 
-    ThreadPool threadPool{ 1 };
     StubFileSource fileSource;
-    Style::Impl style { threadPool, fileSource, 1.0 };
+    Style::Impl style { fileSource, 1.0 };
 
     style.loadJSON(util::read_file("test/fixtures/resources/style-unused-sources.json"));
 
@@ -84,9 +81,8 @@ TEST(Style, RemoveSourceInUse) {
     auto log = new FixtureLogObserver();
     Log::setObserver(std::unique_ptr<Log::Observer>(log));
 
-    ThreadPool threadPool{ 1 };
     StubFileSource fileSource;
-    Style::Impl style { threadPool, fileSource, 1.0 };
+    Style::Impl style { fileSource, 1.0 };
 
     style.loadJSON(util::read_file("test/fixtures/resources/style-unused-sources.json"));