add pixelref->readPixels()

unimplemented (for now) on the gpu side



git-svn-id: http://skia.googlecode.com/svn/trunk@1037 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/SkGrTexturePixelRef.cpp b/src/gpu/SkGrTexturePixelRef.cpp
index da9ac1a..de19f1d 100644
--- a/src/gpu/SkGrTexturePixelRef.cpp
+++ b/src/gpu/SkGrTexturePixelRef.cpp
@@ -27,4 +27,7 @@
     GrSafeUnref(fTexture);
 }
 
+bool SkGrTexturePixelRef::onReadPixels(SkBitmap* dst, const SkIRect* subset) {
+    return false;
+}