[core] Add hooks for setting experimental thread priorities for mbgl threads

platform/default/src/mbgl/storage/asset_file_source.cpp

@@ -1,3 +1,4 @@
+#include <mbgl/platform/settings.hpp>
 #include <mbgl/storage/asset_file_source.hpp>
 #include <mbgl/storage/file_source_request.hpp>
 #include <mbgl/storage/local_file_request.hpp>
@@ -42,8 +43,8 @@ private:
 };
 
 AssetFileSource::AssetFileSource(const std::string& root)
-    : impl(std::make_unique<util::Thread<Impl>>("AssetFileSource", root)) {
-}
+    : impl(std::make_unique<util::Thread<Impl>>(
+          util::makeThreadPrioritySetter(platform::EXPERIMENTAL_THREAD_PRIORITY_FILE), "AssetFileSource", root)) {}
 
 AssetFileSource::~AssetFileSource() = default;
 

platform/default/src/mbgl/storage/database_file_source.cpp

@@ -1,3 +1,4 @@
+#include <mbgl/platform/settings.hpp>
 #include <mbgl/storage/database_file_source.hpp>
 #include <mbgl/storage/file_source_manager.hpp>
 #include <mbgl/storage/file_source_request.hpp>
@@ -7,6 +8,7 @@
 #include <mbgl/storage/response.hpp>
 #include <mbgl/util/constants.hpp>
 #include <mbgl/util/logging.hpp>
+#include <mbgl/util/platform.hpp>
 #include <mbgl/util/thread.hpp>
 
 namespace mbgl {
@@ -149,7 +151,10 @@ class DatabaseFileSource::Impl {
 public:
     Impl(std::shared_ptr<FileSource> onlineFileSource, const std::string& cachePath)
         : thread(std::make_unique<util::Thread<DatabaseFileSourceThread>>(
-              "DatabaseFileSource", std::move(onlineFileSource), cachePath)) {}
+              util::makeThreadPrioritySetter(platform::EXPERIMENTAL_THREAD_PRIORITY_DATABASE),
+              "DatabaseFileSource",
+              std::move(onlineFileSource),
+              cachePath)) {}
 
     ActorRef<DatabaseFileSourceThread> actor() const { return thread->actor(); }
 

platform/default/src/mbgl/storage/local_file_source.cpp

@@ -1,3 +1,4 @@
+#include <mbgl/platform/settings.hpp>
 #include <mbgl/storage/file_source_request.hpp>
 #include <mbgl/storage/local_file_request.hpp>
 #include <mbgl/storage/local_file_source.hpp>
@@ -36,8 +37,8 @@ public:
 };
 
 LocalFileSource::LocalFileSource()
-    : impl(std::make_unique<util::Thread<Impl>>("LocalFileSource")) {
-}
+    : impl(std::make_unique<util::Thread<Impl>>(
+          util::makeThreadPrioritySetter(platform::EXPERIMENTAL_THREAD_PRIORITY_FILE), "LocalFileSource")) {}
 
 LocalFileSource::~LocalFileSource() = default;
 

platform/default/src/mbgl/storage/main_resource_loader.cpp

@@ -1,5 +1,6 @@
 #include <mbgl/actor/actor.hpp>
 #include <mbgl/actor/scheduler.hpp>
+#include <mbgl/platform/settings.hpp>
 #include <mbgl/storage/file_source_manager.hpp>
 #include <mbgl/storage/file_source_request.hpp>
 #include <mbgl/storage/main_resource_loader.hpp>
@@ -131,7 +132,12 @@ public:
           onlineFileSource(std::move(onlineFileSource_)),
           supportsCacheOnlyRequests_(bool(databaseFileSource)),
           thread(std::make_unique<util::Thread<MainResourceLoaderThread>>(
-              "ResourceLoaderThread", assetFileSource, databaseFileSource, localFileSource, onlineFileSource)) {}
+              util::makeThreadPrioritySetter(platform::EXPERIMENTAL_THREAD_PRIORITY_WORKER),
+              "ResourceLoaderThread",
+              assetFileSource,
+              databaseFileSource,
+              localFileSource,
+              onlineFileSource)) {}
 
     std::unique_ptr<AsyncRequest> request(const Resource& resource, Callback callback) {
         auto req = std::make_unique<FileSourceRequest>(std::move(callback));

platform/default/src/mbgl/storage/online_file_source.cpp

@@ -1,8 +1,8 @@
-#include <mbgl/storage/online_file_source.hpp>
+#include <mbgl/platform/settings.hpp>
+#include <mbgl/storage/file_source_request.hpp>
 #include <mbgl/storage/http_file_source.hpp>
 #include <mbgl/storage/network_status.hpp>
-
-#include <mbgl/storage/file_source_request.hpp>
+#include <mbgl/storage/online_file_source.hpp>
 #include <mbgl/storage/resource_transform.hpp>
 #include <mbgl/storage/response.hpp>
 #include <mbgl/util/logging.hpp>
@@ -15,6 +15,7 @@
 #include <mbgl/util/http_timeout.hpp>
 #include <mbgl/util/mapbox.hpp>
 #include <mbgl/util/noncopyable.hpp>
+#include <mbgl/util/platform.hpp>
 #include <mbgl/util/run_loop.hpp>
 #include <mbgl/util/thread.hpp>
 #include <mbgl/util/timer.hpp>
@@ -293,7 +294,9 @@ private:
 
 class OnlineFileSource::Impl {
 public:
-    Impl() : thread(std::make_unique<util::Thread<OnlineFileSourceThread>>("OnlineFileSource")) {}
+    Impl()
+        : thread(std::make_unique<util::Thread<OnlineFileSourceThread>>(
+              util::makeThreadPrioritySetter(platform::EXPERIMENTAL_THREAD_PRIORITY_NETWORK), "OnlineFileSource")) {}
 
     std::unique_ptr<AsyncRequest> request(Callback callback, Resource res) {
         auto req = std::make_unique<FileSourceRequest>(std::move(callback));