Add an origin flag for backend (external) textures.  Some textures in WebKit have a topdown orientation, and skia needs to be notified of this, so that they are not drawn upside-down.

Review URL: https://codereview.appspot.com/7200048

git-svn-id: http://skia.googlecode.com/svn/trunk@7414 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/gpu/GrRenderTarget.h b/include/gpu/GrRenderTarget.h
index 4e77466..19a37a5 100644
--- a/include/gpu/GrRenderTarget.h
+++ b/include/gpu/GrRenderTarget.h
@@ -142,7 +142,7 @@
                    bool isWrapped,
                    GrTexture* texture,
                    const GrTextureDesc& desc,
-                   Origin origin)
+                   GrSurfaceOrigin origin)
         : INHERITED(gpu, isWrapped, desc, origin)
         , fStencilBuffer(NULL)
         , fTexture(texture) {