Fix pure virtual function call (#3979)

src/mbgl/tile/vector_mlt_tile.cpp

@@ -15,6 +15,12 @@ VectorMLTTile::VectorMLTTile(const OverscaledTileID& id_,
                              TileObserver* observer_)
     : VectorTile(id_, std::move(sourceID_), parameters_, tileset_, observer_) {}
 
+VectorMLTTile::~VectorMLTTile() {
+    // Don't rely on `~TileLoader` to close, it's not safe to call there.
+    // We're still calling a virtual method from a destructor, so any overrides will not be called.
+    GeometryTile::cancel();
+}
+
 void VectorMLTTile::setData(const std::shared_ptr<const std::string>& data_) {
     if (!obsolete) {
         GeometryTile::setData(data_ ? std::make_unique<VectorMLTTileData>(data_) : nullptr);

src/mbgl/tile/vector_mlt_tile.hpp

@@ -17,6 +17,8 @@ public:
                   const Tileset&,
                   TileObserver* observer = nullptr);
 
+    ~VectorMLTTile() override;
+
     void setData(const std::shared_ptr<const std::string>& data) override;
 };
 

src/mbgl/tile/vector_mvt_tile.cpp

@@ -15,6 +15,12 @@ VectorMVTTile::VectorMVTTile(const OverscaledTileID& id_,
                              TileObserver* observer_)
     : VectorTile(id_, std::move(sourceID_), parameters_, tileset_, observer_) {}
 
+VectorMVTTile::~VectorMVTTile() {
+    // Don't rely on `~TileLoader` to close, it's not safe to call there.
+    // We're still calling a virtual method from a destructor, so any overrides will not be called.
+    GeometryTile::cancel();
+}
+
 void VectorMVTTile::setData(const std::shared_ptr<const std::string>& data_) {
     if (!obsolete) {
         GeometryTile::setData(data_ ? std::make_unique<VectorMVTTileData>(data_) : nullptr);

src/mbgl/tile/vector_mvt_tile.hpp

@@ -17,6 +17,8 @@ public:
                   const Tileset&,
                   TileObserver* observer = nullptr);
 
+    ~VectorMVTTile() override;
+
     void setData(const std::shared_ptr<const std::string>& data) override;
 };