Add SkRasterPipeline blitter.

src/core/SkColorFilter.cpp

Index: src/core/SkColorFilter.cpp
diff --git a/src/core/SkColorFilter.cpp b/src/core/SkColorFilter.cpp
index 167a6683809732041e598f8e06cf14961a72cc9d..31c0ddb06b27ba4905fce7f777e11ba3d95ee040 100644
--- a/src/core/SkColorFilter.cpp
+++ b/src/core/SkColorFilter.cpp
@@ -37,6 +37,14 @@ sk_sp<GrFragmentProcessor> SkColorFilter::asFragmentProcessor(GrContext*) const
 }
 #endif
 
+bool SkColorFilter::appendStages(SkRasterPipeline* pipeline) const {
+    return this->onAppendStages(pipeline);
+}
+
+bool SkColorFilter::onAppendStages(SkRasterPipeline*) const {
+    return false;
+}
+
 void SkColorFilter::filterSpan4f(const SkPM4f src[], int count, SkPM4f result[]) const {
     const int N = 128;
     SkPMColor tmp[N];