Crash report: https://crash-stats.mozilla.org/report/index/0291a7ff-db48-4b54-9394-5044e0210316

MOZ_CRASH Reason: MOZ_CRASH()

Top 10 frames of crashing thread:

0 mozglue.dll mozalloc_abort memory/mozalloc/mozalloc_abort.cpp:33
1 mozglue.dll mozalloc_handle_oom memory/mozalloc/mozalloc_oom.cpp:51
2 xul.dll gkrust_shared::oom_hook::hook toolkit/library/rust/shared/lib.rs:133
3 xul.dll std::alloc::rust_oom ../cb75ad5db02783e8b0222fee363c5f63f7e2cf5b//library/std/src/alloc.rs:330
4 xul.dll alloc::alloc::__alloc_error_handler::__rg_oom ../cb75ad5db02783e8b0222fee363c5f63f7e2cf5b//library/alloc/src/alloc.rs:397
5 xul.dll _rust_alloc_error_handler 
6 xul.dll alloc::alloc::handle_alloc_error ../cb75ad5db02783e8b0222fee363c5f63f7e2cf5b//library/alloc/src/alloc.rs:366
7 xul.dll webrender::hit_test::add_clips gfx/wr/webrender/src/hit_test.rs:488
8 xul.dll webrender::hit_test::HitTestingScene::add_item gfx/wr/webrender/src/hit_test.rs:212
9 xul.dll webrender::scene_building::SceneBuilder::build_item gfx/wr/webrender/src/scene_building.rs:1156

A new OOM signature from webrender::hit_test::add_clips.

Numbers are low enough that I assume this is just a general memory issue and the vector resize just happens to be the last straw.