Fix null-pointer dereference MapRenderer Android

platform/android/MapboxGLAndroidSDK/src/cpp/map_renderer.cpp

@@ -22,9 +22,12 @@ MapRenderer::MapRenderer(jni::JNIEnv& _env,
       pixelRatio(pixelRatio_),
       localIdeographFontFamily(localIdeographFontFamily_ ? jni::Make<std::string>(_env, localIdeographFontFamily_)
                                                          : optional<std::string>{}),
-      mailboxData(this) {}
+      threadPool(Scheduler::GetBackground()),
+      mailboxData(this),
+      backend(std::make_unique<AndroidRendererBackend>()) {}
 
-MapRenderer::MailboxData::MailboxData(Scheduler* scheduler_) : scheduler(scheduler_) {
+MapRenderer::MailboxData::MailboxData(Scheduler* scheduler_)
+    : scheduler(scheduler_) {
     assert(scheduler);
 }
 
@@ -143,7 +146,7 @@ void MapRenderer::requestSnapshot(SnapshotCallback callback) {
 
 void MapRenderer::resetRenderer() {
     renderer.reset();
-    backend.reset();
+    backend = std::make_unique<AndroidRendererBackend>();
 }
 
 void MapRenderer::scheduleSnapshot(std::unique_ptr<SnapshotCallback> callback) {
@@ -165,6 +168,7 @@ void MapRenderer::render(JNIEnv&) {
     }
 
     // Activate the backend
+    assert(backend);
     gfx::BackendScope backendGuard { *backend };
 
     // Ensure that the "current" scheduler on the render thread is
@@ -190,6 +194,7 @@ void MapRenderer::onSurfaceCreated(JNIEnv&) {
     std::lock_guard<std::mutex> lock(initialisationMutex);
 
     // The GL context is already active if get a new surface.
+    assert(backend);
     gfx::BackendScope backendGuard { *backend, gfx::BackendScope::ScopeType::Implicit };
 
     // The android system will have already destroyed the underlying

platform/android/MapboxGLAndroidSDK/src/cpp/map_renderer.hpp

@@ -114,7 +114,7 @@ class MapRenderer : public Scheduler {
     float pixelRatio;
     optional<std::string> localIdeographFontFamily;
 
-    std::shared_ptr<ThreadPool> threadPool;
+    std::shared_ptr<Scheduler> threadPool;
     const MailboxData mailboxData;
 
     std::mutex initialisationMutex;