First blitter for linear pipeline.

src/core/SkLinearBitmapPipeline.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkLinearBitmapPipeline_DEFINED
 #define SkLinearBitmapPipeline_DEFINED
 
 #include "SkColor.h"
 #include "SkImageInfo.h"
 #include "SkMatrix.h"
 #include "SkShader.h"
 
 class SkLinearBitmapPipeline {
 public:
     SkLinearBitmapPipeline(
         const SkMatrix& inverse,
         SkFilterQuality filterQuality,
         SkShader::TileMode xTile, SkShader::TileMode yTile,
         float postAlpha,
         const SkPixmap& srcPixmap);
+
+    SkLinearBitmapPipeline(
+        const SkLinearBitmapPipeline& pipeline,
+        SkXfermode::Mode mode,
+        const SkPixmap& srcPixmap,
+        const SkImageInfo& dstInfo);
+
     ~SkLinearBitmapPipeline();
 
     void shadeSpan4f(int x, int y, SkPM4f* dst, int count);
+    void blitSpan(int32_t x, int32_t y, void* dst, int count);
 
     template<typename Base, size_t kSize, typename Next = void>
     class Stage {
     public:
         Stage() : fIsInitialized{false} {}
         ~Stage();
 
         template<typename Variant, typename... Args>
         void initStage(Next* next, Args&& ... args);
 
@@ skipping 21 matching lines @@
         bool fIsInitialized;
         mutable Space fSpace;
     };
 
     class PointProcessorInterface;
     class SampleProcessorInterface;
     class BlendProcessorInterface;
     class DestinationInterface;
 
     // These values were generated by the assert above in Stage::init{Sink|Stage}.
-    using MatrixStage  = Stage<PointProcessorInterface, 160, PointProcessorInterface>;
-    using TileStage    = Stage<PointProcessorInterface, 160, SampleProcessorInterface>;
+    using MatrixStage  = Stage<PointProcessorInterface,  160, PointProcessorInterface>;
+    using TileStage    = Stage<PointProcessorInterface,  160, SampleProcessorInterface>;
     using SampleStage  = Stage<SampleProcessorInterface, 100, BlendProcessorInterface>;
-    using BlenderStage = Stage<BlendProcessorInterface, 80>;
+    using BlenderStage = Stage<BlendProcessorInterface,   40>;
 
 private:
     PointProcessorInterface* fFirstStage;
     MatrixStage              fMatrixStage;
     TileStage                fTileStage;
     SampleStage              fSampleStage;
     BlenderStage             fBlenderStage;
     DestinationInterface*    fLastStage;
 };
 
 #endif  // SkLinearBitmapPipeline_DEFINED