Bugzilla

Crash report: https://crash-stats.mozilla.org/report/index/fc138aa9-5df6-47f6-9ce1-073cb0220518

MOZ_CRASH Reason: ```bug: this is an unexpected case - please open a bug and talk to #gfx team!```

Top 10 frames of crashing thread:
```
0 libxul.so RustMozCrash mozglue/static/rust/wrappers.cpp:18
1 libxul.so mozglue_static::panic_hook mozglue/static/rust/lib.rs:91
2 libxul.so core::ops::function::Fn::call library/core/src/ops/function.rs:70
3 libxul.so std::panicking::rust_panic_with_hook library/std/src/panicking.rs:702
4 libxul.so std::panicking::begin_panic::{{closure}} library/std/src/panicking.rs:617
5 libxul.so std::sys_common::backtrace::__rust_end_short_backtrace library/std/src/sys_common/backtrace.rs:138
6 libxul.so std::panicking::begin_panic library/std/src/panicking.rs:616
7 libxul.so webrender::spatial_tree::SpatialTree::get_relative_transform_with_face gfx/wr/webrender/src/spatial_tree.rs:973
8 libxul.so webrender::picture::PicturePrimitive::assign_surface gfx/wr/webrender/src/picture.rs:5882
9 libxul.so webrender::picture_graph::PictureGraph::assign_surfaces gfx/wr/webrender/src/picture_graph.rs:108
```
Steps to reproduce:

1) Navigate to https://codepen.io/islamghany/full/BaajZXW
2) Click "Open Model"

Actual results: Firefox crashes
Expected result: Firefox does not crash

Crash report: https://crash-stats.mozilla.org/report/index/fc138aa9-5df6-47f6-9ce1-073cb0220518

MOZ_CRASH Reason: ```bug: this is an unexpected case - please open a bug and talk to #gfx team!```

Top 10 frames of crashing thread:
```
0 libxul.so RustMozCrash mozglue/static/rust/wrappers.cpp:18
1 libxul.so mozglue_static::panic_hook mozglue/static/rust/lib.rs:91
2 libxul.so core::ops::function::Fn::call library/core/src/ops/function.rs:70
3 libxul.so std::panicking::rust_panic_with_hook library/std/src/panicking.rs:702
4 libxul.so std::panicking::begin_panic::{{closure}} library/std/src/panicking.rs:617
5 libxul.so std::sys_common::backtrace::__rust_end_short_backtrace library/std/src/sys_common/backtrace.rs:138
6 libxul.so std::panicking::begin_panic library/std/src/panicking.rs:616
7 libxul.so webrender::spatial_tree::SpatialTree::get_relative_transform_with_face gfx/wr/webrender/src/spatial_tree.rs:973
8 libxul.so webrender::picture::PicturePrimitive::assign_surface gfx/wr/webrender/src/picture.rs:5882
9 libxul.so webrender::picture_graph::PictureGraph::assign_surfaces gfx/wr/webrender/src/picture_graph.rs:108
```
Steps to reproduce:

1) Set `layout.css.backdrop-filter.enabled` to `true` in about:config
2) Navigate to https://codepen.io/islamghany/full/BaajZXW
3) Click "Open Model"

Actual results: Firefox crashes
Expected result: Firefox does not crash