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/src/gpu/effects/GrTextureDomainEffect.cpp b/src/gpu/effects/GrTextureDomainEffect.cpp
index bfd62c2..833c198 100644
--- a/src/gpu/effects/GrTextureDomainEffect.cpp
+++ b/src/gpu/effects/GrTextureDomainEffect.cpp
@@ -90,7 +90,7 @@
         SkScalarToFloat(domain.bottom())
     };
     // vertical flip if necessary
-    if (GrSurface::kBottomLeft_Origin == effect.texture(0)->origin()) {
+    if (kBottomLeft_GrSurfaceOrigin == effect.texture(0)->origin()) {
         values[1] = 1.0f - values[1];
         values[3] = 1.0f - values[3];
         // The top and bottom were just flipped, so correct the ordering