Auto merge of #29748 - Loirooriol:sync, r=mrobinson

Backport several style changes from Gecko

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components/layout_thread_2020/lib.rs

@@ -82,7 +82,7 @@ use style::animation::DocumentAnimationSet;
 use style::context::{
     QuirksMode, RegisteredSpeculativePainter, RegisteredSpeculativePainters, SharedStyleContext,
 };
-use style::dom::{TDocument, TElement, TNode};
+use style::dom::{TElement, TNode};
 use style::driver;
 use style::error_reporting::RustLogReporter;
 use style::global_style_data::{GLOBAL_STYLE_DATA, STYLE_THREAD_POOL};
@@ -943,11 +943,7 @@ impl LayoutThread {
         }
 
         // Flush shadow roots stylesheets if dirty.
-        document.flush_shadow_roots_stylesheets(
-            &self.stylist.device(),
-            document.quirks_mode(),
-            guards.author.clone(),
-        );
+        document.flush_shadow_roots_stylesheets(&mut self.stylist, guards.author.clone());
 
         let restyles = std::mem::take(&mut data.pending_restyles);
         debug!("Draining restyles: {}", restyles.len());