From b5800a6de2371cade827f4b8820f530877fad32b Mon Sep 17 00:00:00 2001
From: Matt Woodrow <mwoodrow@mozilla.com>
Date: Mon, 27 Nov 2017 16:47:28 +1300
Subject: [PATCH] Bug 1420312 - Followup to only mark frame as modified during
 retained building, since otherwise it won't be restored.

--HG--
extra : rebase_source : 675d7b40da6c41f2b2bc1513bee72e3361cbcd33
---
 layout/generic/nsFrame.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/layout/generic/nsFrame.cpp b/layout/generic/nsFrame.cpp
index a67354c05db4..8d26aa422ade 100644
--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -2758,8 +2758,10 @@ nsIFrame::BuildDisplayListForStackingContext(nsDisplayListBuilder* aBuilder,
 
     // We rebuild everything within preserve-3d and don't try
     // to retain, so override the dirty rect now.
-    dirtyRect = visibleRect;
-    aBuilder->MarkFrameModifiedDuringBuilding(this);
+    if (aBuilder->IsRetainingDisplayList()) {
+      dirtyRect = visibleRect;
+      aBuilder->MarkFrameModifiedDuringBuilding(this);
+    }
   }
 
   bool inTransform = aBuilder->IsInTransform();