[android] Custom layer bindings

src/mbgl/map/map_context.cpp

@@ -285,6 +285,8 @@ double MapContext::getTopOffsetPixelsForAnnotationIcon(const std::string& name)
 
 void MapContext::addLayer(std::unique_ptr<StyleLayer> layer, mapbox::util::optional<std::string> after) {
     style->addLayer(std::move(layer), after);
+    updateFlags |= Update::Classes;
+    asyncUpdate.send();
 }
 
 void MapContext::setSourceTileCacheSize(size_t size) {