From e0c25a9459b3e643d4fd06b773092e6f8d073052 Mon Sep 17 00:00:00 2001
From: Jim Mathies <jmathies@mozilla.com>
Date: Mon, 19 Oct 2015 10:38:42 -0500
Subject: [PATCH] Bug 1213758 - Aquire the inderect layer trees data lock
 during plugin window update calculations. r=matt.woodrow

---
 gfx/layers/ipc/CompositorParent.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/gfx/layers/ipc/CompositorParent.cpp b/gfx/layers/ipc/CompositorParent.cpp
index 615b309d29eb..3c936c3d00f8 100644
--- a/gfx/layers/ipc/CompositorParent.cpp
+++ b/gfx/layers/ipc/CompositorParent.cpp
@@ -2057,7 +2057,13 @@ CrossProcessCompositorParent::ShadowLayersUpdated(
 bool
 CompositorParent::UpdatePluginWindowState(uint64_t aId)
 {
+  MonitorAutoLock lock(*sIndirectLayerTreesLock);
   CompositorParent::LayerTreeState& lts = sIndirectLayerTrees[aId];
+  if (!lts.mParent) {
+    PLUGINS_LOG("[%" PRIu64 "] layer tree compositor parent pointer is null", aId);
+    return false;
+  }
+
   // Check if this layer tree has received any shadow layer updates
   if (!lts.mUpdatedPluginDataAvailable) {
     PLUGINS_LOG("[%" PRIu64 "] no plugin data", aId);