From 8ae1cd588c1060e309b8de482f5032ea38236d48 Mon Sep 17 00:00:00 2001
From: Martin Robinson <mrobinson@igalia.com>
Date: Fri, 1 Aug 2025 22:50:12 +0200
Subject: [PATCH] ResizeObserver shouldn't always force a rendering update

---
 components/script/dom/document.rs  |  3 ---
 components/script/script_thread.rs | 10 ++++------
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 68d0b4a2f16..80df1a4d003 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -3670,9 +3670,6 @@ impl Document {
         if self.has_pending_input_events() {
             return true;
         }
-        if self.has_resize_observers() {
-            return true;
-        }
         if self.window().has_unhandled_resize_event() {
             return true;
         }
diff --git a/components/script/script_thread.rs b/components/script/script_thread.rs
index ce4c74d28ae..6c77be8c9ad 100644
--- a/components/script/script_thread.rs
+++ b/components/script/script_thread.rs
@@ -1377,12 +1377,10 @@ impl ScriptThread {
     fn maybe_schedule_rendering_opportunity_after_rendering_update(&self, saw_any_reflows: bool) {
         // If there are any pending reflows and we are not having rendering opportunities
         // immediately after running "update the rendering," run it one more time.
-        if self
-            .documents
-            .borrow()
-            .iter()
-            .any(|(_, document)| document.needs_rendering_update())
-        {
+        if self.documents.borrow().iter().any(|(_, document)| {
+            document.needs_rendering_update() ||
+                (saw_any_reflows && document.has_resize_observers())
+        }) {
             self.cancel_scheduled_update_the_rendering();
             self.schedule_update_the_rendering_timer_if_necessary(Duration::ZERO);
         }