From 35bbcc0d9519411dd1112dece8df19ddca51276c Mon Sep 17 00:00:00 2001
From: Martin Robinson <mrobinson@igalia.com>
Date: Mon, 10 Jun 2024 15:32:30 +0200
Subject: [PATCH] script: Remove explicit reflow for web font loads (#32455)

Instead of using an explicit reflow when a web font laods, queue a
pending reflow. This should be able to eliminate multiple reflows some
situations. A followup should ensure that only nodes that have pending
fonts loading are reflows, but this change is the first step.
---
 components/script/dom/window.rs                      |  1 -
 components/script/script_thread.rs                   | 12 ++++++++----
 .../before-after-dynamic-attr-001.xht.ini            |  3 ---
 3 files changed, 8 insertions(+), 8 deletions(-)
 delete mode 100644 tests/wpt/meta-legacy-layout/css/CSS2/generated-content/before-after-dynamic-attr-001.xht.ini

diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index 5dbbc3f2377..a86dcfc4ed8 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -182,7 +182,6 @@ pub enum ReflowReason {
     StylesheetLoaded,
     Timer,
     Viewport,
-    WebFontLoaded,
     WindowResize,
     WorkletLoaded,
 }
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index f3b13f8deb8..ffcfb98daac 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -3273,10 +3273,14 @@ impl ScriptThread {
 
     /// Handles a Web font being loaded. Does nothing if the page no longer exists.
     fn handle_web_font_loaded(&self, pipeline_id: PipelineId) {
-        let document = self.documents.borrow().find_document(pipeline_id);
-        if let Some(document) = document {
-            self.rebuild_and_force_reflow(&document, ReflowReason::WebFontLoaded);
-        }
+        let Some(document) = self.documents.borrow().find_document(pipeline_id) else {
+            warn!("Web font loaded in closed pipeline {}.", pipeline_id);
+            return;
+        };
+
+        // TODO: This should only dirty nodes that are waiting for a web font to finish loading!
+        document.dirty_all_nodes();
+        document.window().add_pending_reflow();
     }
 
     /// Handles a worklet being loaded. Does nothing if the page no longer exists.
diff --git a/tests/wpt/meta-legacy-layout/css/CSS2/generated-content/before-after-dynamic-attr-001.xht.ini b/tests/wpt/meta-legacy-layout/css/CSS2/generated-content/before-after-dynamic-attr-001.xht.ini
deleted file mode 100644
index e0d367787bb..00000000000
--- a/tests/wpt/meta-legacy-layout/css/CSS2/generated-content/before-after-dynamic-attr-001.xht.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[before-after-dynamic-attr-001.xht]
-  type: reftest
-  expected: FAIL