From 6f63dc2cc3485676e9c03d90dc53b91ed1171397 Mon Sep 17 00:00:00 2001
From: Cameron Kaiser <classilla@floodgap.com>
Date: Tue, 13 Aug 2019 19:24:38 -0700
Subject: [PATCH] #565: M1367219

---
 layout/base/FrameLayerBuilder.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/layout/base/FrameLayerBuilder.cpp b/layout/base/FrameLayerBuilder.cpp
index 864f83682..3d0d9447d 100644
--- a/layout/base/FrameLayerBuilder.cpp
+++ b/layout/base/FrameLayerBuilder.cpp
@@ -243,8 +243,13 @@ FrameLayerBuilder::DisplayItemData::~DisplayItemData()
     array->RemoveElement(this);
   }
 
-  MOZ_RELEASE_ASSERT(sAliveDisplayItemDatas && sAliveDisplayItemDatas->Contains(this));
-  sAliveDisplayItemDatas->RemoveEntry(this);
+  MOZ_RELEASE_ASSERT(sAliveDisplayItemDatas);
+  nsPtrHashKey<FrameLayerBuilder::DisplayItemData>* entry
+    = sAliveDisplayItemDatas->GetEntry(this);
+  MOZ_RELEASE_ASSERT(entry);
+
+  sAliveDisplayItemDatas->RemoveEntry(entry);
+
   if (sAliveDisplayItemDatas->Count() == 0) {
     delete sAliveDisplayItemDatas;
     sAliveDisplayItemDatas = nullptr;