From 8ea56f7f6991119095514de930926d2fd41943a2 Mon Sep 17 00:00:00 2001
From: Ethan Lin <etlin@mozilla.com>
Date: Tue, 19 May 2015 00:37:00 -0400
Subject: [PATCH] Bug 1166165 - Check if the timestamp is null to prevent
 assertion. r=nical

---
 gfx/layers/composite/LayerManagerComposite.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gfx/layers/composite/LayerManagerComposite.cpp b/gfx/layers/composite/LayerManagerComposite.cpp
index 0e8744a2491..cc5dabe4994 100644
--- a/gfx/layers/composite/LayerManagerComposite.cpp
+++ b/gfx/layers/composite/LayerManagerComposite.cpp
@@ -417,7 +417,7 @@ LayerManagerComposite::RenderDebugOverlay(const Rect& aBounds)
     // Draw a translation delay warning overlay
     int width;
     int border;
-    if ((now - mWarnTime).ToMilliseconds() < kVisualWarningDuration) {
+    if (!mWarnTime.IsNull() && (now - mWarnTime).ToMilliseconds() < kVisualWarningDuration) {
       EffectChain effects;
 
       // Black blorder