Guard against null surface in Image::updateSurface.
Review URL: https://codereview.appspot.com/5985051

git-svn-id: https://angleproject.googlecode.com/svn/trunk@1026 736b8ea6-26fd-11df-bfd4-992fa37f6226
diff --git a/src/libGLESv2/Texture.cpp b/src/libGLESv2/Texture.cpp
index 36228f9..003776f 100644
--- a/src/libGLESv2/Texture.cpp
+++ b/src/libGLESv2/Texture.cpp
@@ -264,7 +264,7 @@
 {
     IDirect3DSurface9 *sourceSurface = getSurface();
 
-    if (sourceSurface != destSurface)
+    if (sourceSurface && sourceSurface != destSurface)
     {
         RECT rect = transformPixelRect(xoffset, yoffset, width, height, mHeight);