From 7841da0a8110712b2cef893bdb8ef93950352a57 Mon Sep 17 00:00:00 2001
From: Nicolas Silva <nical@mozilla.com>
Date: Wed, 11 Dec 2013 18:32:41 +0100
Subject: [PATCH] Bug 948955 - AddMaskEffect handles locking failure. r=bjacob

---
 gfx/layers/composite/CompositableHost.cpp      | 6 ++----
 gfx/layers/composite/LayerManagerComposite.cpp | 4 +++-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/gfx/layers/composite/CompositableHost.cpp b/gfx/layers/composite/CompositableHost.cpp
index 04edab1be3e2..6e3a71501ddc 100644
--- a/gfx/layers/composite/CompositableHost.cpp
+++ b/gfx/layers/composite/CompositableHost.cpp
@@ -136,13 +136,11 @@ CompositableHost::AddMaskEffect(EffectChain& aEffects,
 {
   RefPtr<TextureSource> source;
   RefPtr<DeprecatedTextureHost> oldHost = GetDeprecatedTextureHost();
-  if (oldHost) {
-    oldHost->Lock();
+  if (oldHost && oldHost->Lock()) {
     source = oldHost;
   } else {
     RefPtr<TextureHost> host = GetAsTextureHost();
-    if (host) {
-      host->Lock();
+    if (host && host->Lock()) {
       source = host->GetTextureSources();
     }
   }
diff --git a/gfx/layers/composite/LayerManagerComposite.cpp b/gfx/layers/composite/LayerManagerComposite.cpp
index e16fbb2d6a21..7ac217f24c61 100644
--- a/gfx/layers/composite/LayerManagerComposite.cpp
+++ b/gfx/layers/composite/LayerManagerComposite.cpp
@@ -726,7 +726,9 @@ LayerManagerComposite::AutoAddMaskEffect::AutoAddMaskEffect(Layer* aMaskLayer,
 
   gfx::Matrix4x4 transform;
   ToMatrix4x4(aMaskLayer->GetEffectiveTransform(), transform);
-  mCompositable->AddMaskEffect(aEffects, transform, aIs3D);
+  if (!mCompositable->AddMaskEffect(aEffects, transform, aIs3D)) {
+    mCompositable = nullptr;
+  }
 }
 
 LayerManagerComposite::AutoAddMaskEffect::~AutoAddMaskEffect()