From a2da19760ea8610331430c88d50dcadd0950272c Mon Sep 17 00:00:00 2001
From: roytam1 <roytam@gmail.com>
Date: Sun, 3 Aug 2025 09:28:30 +0800
Subject: [PATCH] layout: CascadeSheet: check aSheet is non-null before use.

fix crash when adblock plus is blocking a stylesheet.
---
 layout/style/nsCSSRuleProcessor.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/layout/style/nsCSSRuleProcessor.cpp b/layout/style/nsCSSRuleProcessor.cpp
index 974284d501..b10cf5f6b1 100644
--- a/layout/style/nsCSSRuleProcessor.cpp
+++ b/layout/style/nsCSSRuleProcessor.cpp
@@ -663,7 +663,7 @@ CascadeRuleEnumFunc(css::Rule* aRule, void* aData)
 /* static */ bool
 nsCSSRuleProcessor::CascadeSheet(CSSStyleSheet* aSheet, CascadeLayer* aLayer)
 {
-  if (aSheet->IsApplicable() &&
+  if (aSheet && aSheet->IsApplicable() &&
       aSheet->UseForPresentation(aLayer->mPresContext,
                                  aLayer->mCacheKey) &&
       aSheet->mInner) {