[core] split off render layers

src/mbgl/renderer/render_custom_layer.cpp

@@ -0,0 +1,26 @@
+#include <mbgl/renderer/render_custom_layer.hpp>
+#include <mbgl/style/layers/custom_layer_impl.hpp>
+#include <mbgl/renderer/bucket.hpp>
+
+namespace mbgl {
+
+RenderCustomLayer::RenderCustomLayer(const style::CustomLayer::Impl& _impl)
+        : RenderLayer(style::LayerType::Custom, _impl),
+          impl(&_impl) {
+}
+
+std::unique_ptr<RenderLayer> RenderCustomLayer::clone() const {
+    return std::make_unique<RenderCustomLayer>(*this);
+}
+
+bool RenderCustomLayer::evaluate(const style::PropertyEvaluationParameters&) {
+    passes = RenderPass::Translucent;
+    return false;
+}
+
+std::unique_ptr<Bucket> RenderCustomLayer::createBucket(const BucketParameters&, const std::vector<const RenderLayer*>&) const {
+    assert(false);
+    return nullptr;
+}
+    
+}