Add SkRasterPipeline blitter.

include/core/SkColorFilter.h

Index: include/core/SkColorFilter.h
diff --git a/include/core/SkColorFilter.h b/include/core/SkColorFilter.h
index 7b2ee7845e1099c0cb549a1d58a88aa2becac973..609550f6762409a8d0e9c29e08eb8931faf5fd59 100644
--- a/include/core/SkColorFilter.h
+++ b/include/core/SkColorFilter.h
@@ -16,6 +16,7 @@
 class GrContext;
 class GrFragmentProcessor;
 class SkBitmap;
+class SkRasterPipeline;
 
 /**
  *  ColorFilters are optional objects in the drawing pipeline. When present in
@@ -70,6 +71,8 @@ public:
 
     virtual void filterSpan4f(const SkPM4f src[], int count, SkPM4f result[]) const;
 
+    bool appendStages(SkRasterPipeline*) const;
+
     enum Flags {
         /** If set the filter methods will not change the alpha channel of the colors.
         */
@@ -168,6 +171,8 @@ public:
 protected:
     SkColorFilter() {}
 
+    virtual bool onAppendStages(SkRasterPipeline*) const;
+
 private:
     /*
      *  Returns 1 if this is a single filter (not a composition of other filters), otherwise it