From 7f4a92ec55eac3620fafe0f343d5aeaec37d610c Mon Sep 17 00:00:00 2001
From: roytam1 <roytam@gmail.com>
Date: Thu, 13 Feb 2025 21:02:15 +0800
Subject: [PATCH] import from mozilla: Bug 1350925 part 1 - Reset the scrolled
 frame's ReflowOutput overflow areas before re-using it for another child
 reflow.  r=dholbert a=gchang (8c70d11ecd1)

---
 layout/generic/nsGfxScrollFrame.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/layout/generic/nsGfxScrollFrame.cpp b/layout/generic/nsGfxScrollFrame.cpp
index 8328f70da5..f7eeef2f42 100644
--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -365,6 +365,7 @@ nsHTMLScrollFrame::TryLayout(ScrollReflowInput* aState,
       nsLayoutUtils::MarkIntrinsicISizesDirtyIfDependentOnBSize(
           mHelper.mScrolledFrame);
     }
+    aKidMetrics->mOverflowAreas.Clear();
     ReflowScrolledFrame(aState, aAssumeHScroll, aAssumeVScroll, aKidMetrics,
                         false);
   }
@@ -719,6 +720,7 @@ nsHTMLScrollFrame::ReflowContents(ScrollReflowInput* aState,
                                                insideBorderSize);
     if (nsRect(nsPoint(0, 0), insideBorderSize).Contains(scrolledRect)) {
       // Let's pretend we had no scrollbars coming in here
+      kidDesiredSize.mOverflowAreas.Clear();
       ReflowScrolledFrame(aState, false, false, &kidDesiredSize, false);
     }
   }