From 2f416d4188e35b09b60671d8a7efa7cbc6fea4b2 Mon Sep 17 00:00:00 2001
From: Timothy Nikkel <tnikkel@gmail.com>
Date: Thu, 26 Aug 2010 22:01:43 -0500
Subject: [PATCH] imported patch returnnullincreatesimilar

---
 gfx/thebes/gfxASurface.cpp    | 4 ++++
 gfx/thebes/gfxXlibSurface.cpp | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/gfx/thebes/gfxASurface.cpp b/gfx/thebes/gfxASurface.cpp
index bc04330d125..0ff6309a395 100644
--- a/gfx/thebes/gfxASurface.cpp
+++ b/gfx/thebes/gfxASurface.cpp
@@ -310,6 +310,10 @@ already_AddRefed<gfxASurface>
 gfxASurface::CreateSimilarSurface(gfxContentType aContent,
                                   const gfxIntSize& aSize)
 {
+    if (!mSurface || !mSurfaceValid) {
+      return nsnull;
+    }
+    
     cairo_surface_t *surface =
         cairo_surface_create_similar(mSurface, cairo_content_t(aContent),
                                      aSize.width, aSize.height);
diff --git a/gfx/thebes/gfxXlibSurface.cpp b/gfx/thebes/gfxXlibSurface.cpp
index 1fc7f4821a0..9b5621e3575 100644
--- a/gfx/thebes/gfxXlibSurface.cpp
+++ b/gfx/thebes/gfxXlibSurface.cpp
@@ -182,6 +182,10 @@ already_AddRefed<gfxASurface>
 gfxXlibSurface::CreateSimilarSurface(gfxContentType aContent,
                                      const gfxIntSize& aSize)
 {
+    if (!mSurface || !mSurfaceValid) {
+      return nsnull;
+    }
+
     if (aContent == CONTENT_COLOR) {
         // cairo_surface_create_similar will use a matching visual if it can.
         // However, systems with 16-bit or indexed default visuals may benefit