Intermittent timeout in /css-backgrounds-3_dev/html4/background-paint-order-001.htm

[asajeffrey]

In #11476 (comment):

  ▶ TIMEOUT [expected PASS] /css-backgrounds-3_dev/html4/background-paint-order-001.htm
  │ 
  │ Xlib:  extension "XFree86-VidModeExtension" missing on display ":0".
  │ Shutting down the Constellation after generating an output file or exit flag specified
  │ Xlib:  extension "XFree86-VidModeExtension" missing on display ":0".
  │ thread 'LayoutWorker worker 9/12' panicked at 'called `Result::unwrap()` on an `Err` value: IoError(Error { repr: Os { code: 104, message: "Connection reset by peer" } })', ../src/libcore/result.rs:785
  │ stack backtrace:
  │    1:     0x7f11ccdd01c0 - std::sys::backtrace::tracing::imp::write::h9fb600083204ae7f
  │    2:     0x7f11ccdd7deb - std::panicking::default_hook::_$u7b$$u7b$closure$u7d$$u7d$::hca543c34f11229ac
  │    3:     0x7f11ccdd7a53 - std::panicking::default_hook::hc2c969e7453d080c
  │    4:     0x7f11cca55277 - util::panicking::initiate_panic_hook::_$u7b$$u7b$closure$u7d$$u7d$::_$u7b$$u7b$closure$u7d$$u7d$::he2b22674ad1748f3
  │    5:     0x7f11ccdbddac - std::panicking::rust_panic_with_hook::hfe203e3083c2b544
  │    6:     0x7f11ccdd8031 - std::panicking::begin_panic::h4889569716505182
  │    7:     0x7f11ccdbf80a - std::panicking::begin_panic_fmt::h484cd47786497f03
  │    8:     0x7f11ccdd7fce - rust_begin_unwind
  │    9:     0x7f11cce0e5cf - core::panicking::panic_fmt::h257ceb0aa351d801
  │   10:     0x7f11cc635d43 - core::result::unwrap_failed::h1d94443d858a91df
  │   11:     0x7f11cc659884 - gfx::font_cache_thread::FontCacheThread::find_font_template::h5b87de1d4383ad19
  │   12:     0x7f11cc65e7d4 - gfx::font_context::FontContext::layout_font_group_for_style::habc798e1e1f378d1
  │   13:     0x7f11cb4f6642 - layout::text::font_metrics_for_style::h47d9ef1163e2ab90
  │   14:     0x7f11cb4f6598 - layout::fragment::Fragment::calculate_line_</span><span class="stdout">height::h2fd722b6e5d0ee10
  │   15:     0x7f11cb4f7f86 - layout::fragment::Fragment::inline_metrics::hb73a427b21f4f6d6
  │   16:     0x7f11cb4fcb60 - layout::inline::LineBreaker::new_block_size_for_line::hb4e8eab4e7d35075
  │   17:     0x7f11cb4ff0b6 - _&lt;layout..inline..InlineFlow as layout..flow..Flow&gt;::assign_block_size::hf126b56b43fc68dc
  │   18:     0x7f11cb5e1cc3 - _&lt;layout..traversal..AssignISizes&lt;&#39;a&gt; as layout..parallel..ParallelPreorderFlowTraversal&gt;::run_parallel::hc10616c74c94e0bf
  │   19:     0x7f11cb5e247f - layout::parallel::assign_inline_sizes::h917782c09b72a5f7
  │   20:     0x7f11cb529aa6 - std::panicking::try::call::ha4fefec3c980f4a5
  │   21:     0x7f11ccde222b - __rust_try
  │   22:     0x7f11ccde21ce - __rust_maybe_catch_panic
  │   23:     0x7f11cb52b337 - _&lt;F as alloc..boxed..FnBox&lt;A&gt;&gt;::call_box::h82fb0d1a3a0ebea9
  │   24:     0x7f11ccdd61d4 - std::sys::thread::Thread::new::thread_start::h6f266e069bf4ec2b
  │   25:     0x7f11c8c44181 - start_thread
  │   26:     0x7f11c875b47c - __clone
  └   27:                0x0 - &lt;unknown&gt;

[jdm]

Similar symptom to #12872.

[jdm]

This is #13492.