From c50bd6b87c4e434b01360c1e25eaaf04ee041a81 Mon Sep 17 00:00:00 2001
From: Matt Woodrow <mwoodrow@mozilla.com>
Date: Mon, 15 Oct 2012 17:53:37 +1300
Subject: [PATCH] Bug 799956 - Mark BasicLayerManagers that don't retain
 content as supporting component alpha layers. r=roc

---
 gfx/layers/basic/BasicLayers.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gfx/layers/basic/BasicLayers.h b/gfx/layers/basic/BasicLayers.h
index d1cb996cffbe..10cc4ee67d9b 100644
--- a/gfx/layers/basic/BasicLayers.h
+++ b/gfx/layers/basic/BasicLayers.h
@@ -93,7 +93,7 @@ public:
   virtual void EndTransaction(DrawThebesLayerCallback aCallback,
                               void* aCallbackData,
                               EndTransactionFlags aFlags = END_DEFAULT);
-  virtual bool AreComponentAlphaLayersEnabled() { return HasShadowManager(); }
+  virtual bool AreComponentAlphaLayersEnabled() { return HasShadowManager() || !IsWidgetLayerManager(); }
 
   void AbortTransaction();