Add point spans, but fall back for all cases.

src/core/SkLinearBitmapPipeline.h

Index: src/core/SkLinearBitmapPipeline.h
diff --git a/src/core/SkLinearBitmapPipeline.h b/src/core/SkLinearBitmapPipeline.h
index 5f9da1ea4ca486e4b0a603a71eab1a6321c9f216..f92afad95e2d9a810583e732c3f73cf21d638518 100644
--- a/src/core/SkLinearBitmapPipeline.h
+++ b/src/core/SkLinearBitmapPipeline.h
@@ -22,6 +22,7 @@ public:
     virtual ~PointProcessorInterface() { }
     virtual void pointListFew(int n, Sk4fArg xs, Sk4fArg ys) = 0;
     virtual void pointList4(Sk4fArg xs, Sk4fArg ys) = 0;
+    virtual void pointSpan(SkPoint start, SkScalar length, int count) = 0;
 };
 
 class BilerpProcessorInterface : public PointProcessorInterface {