[core] custom layer - add contextLost callback

- optional callback method that can be used to do cleanup when the context has been lost before re-initialisation

1 files changed, 6 insertions, 2 deletions

diff --git a/src/mbgl/renderer/layers/render_custom_layer.cpp b/src/mbgl/renderer/layers/render_custom_layer.cpp
index 3d19f5ef46..7ece3970da 100644
--- a/src/mbgl/renderer/layers/render_custom_layer.cpp
+++ b/src/mbgl/renderer/layers/render_custom_layer.cpp
@@ -16,8 +16,12 @@ RenderCustomLayer::RenderCustomLayer(Immutable<style::CustomLayer::Impl> _impl)
 
 RenderCustomLayer::~RenderCustomLayer() {
     assert(BackendScope::exists());
-    if (initialized && !contextDestroyed && impl().deinitializeFn) {
-        impl().deinitializeFn(impl().context);
+    if (initialized) {
+        if (contextDestroyed && impl().contextLostFn ) {
+            impl().contextLostFn(impl().context);
+        } else if (!contextDestroyed && impl().deinitializeFn) {
+            impl().deinitializeFn(impl().context);
+        }
     }
 }